The basic needs of a human consist of being fed, have his/her body covered and protection of hush weather conditions, in that order.
Having enough to eat is the first and most important need that must be addressed. A person will first feed himself before anything else. This need is so strong that a person will kill to have it met.
Secondly, all humans have the need to be clothed. This is the need to be comfortable at all times. People have made themselves clothes from animal skins since early times and later on weaved material from plant fibers (natural fibers). These days fibers to weaved into cloth is obtained not only from plants but also from synthetic fibers (man-made fibers).
Lastly, you need a roof over your head because clothing won’t keep you comfortable at all times. Because extreme weather conditions can not be withstand by being clothed alone.
This is the need I’d like to address. From early times the human race, like a lot of other animals, hide in caves or build some structure to hide in at nights. Even during the bad weather conditions, especially during winter dwellings are essential for survival.
These dwellings always need to be maintained, whether it’s a cave or a self-made structure, in order to keep us comfortable. Early humans knew this very well and thus added improvements and restoration material to these dwellings on a regular basis.
Here are three maintenance areas to your home that must be taken into consideration.
1 Roof repairs.
The roof on your home forms a very important piece of your house. Not only does it protect you, your belongings and other residents and keep you comfortable but also keep them protected from the sun, rain and during winter storms.
1.2 Problem with roofs.
On this planet, we live on, roof structures that do not last forever. There is always a degree of deterioration going on. (“Time erodes us all.” ? Meg Rosoff, What I Was) If rust does not eat away on you roof termites and other insects will. And I’m not even talking about mold.
Don’t be fooled, your roof will not last forever. It needs to be attended to regularly. Remember that even treated wood can and will deteriorate if not looked after. Iron structures and zinc roof sheets do rust, even if treated, when not attended to. Things like fallen leaves and dust accumulate, mostly on lower sections. When water, in the form of rainwater, is added you will sit with a rusted roof.
Rust of iron structures occurs when not properly protected and definitely if not looked after. The same goes for zinc roof sheets as well as tiles like Harvey tiles. Although Harvey tiles are properly treated against the weather one does find deterioration from time to time. In the case of concrete and clay roofs, you will get an accumulation of mold growth with the risk of the occupants of the house getting sick.
Water is a force on its own. It will wash away a complete structure and penetrate your roof ceilings and walls, causing damp which causes a lot of damage. This leads to the replacement of roof coverings, roof structure, ceilings and plastering on your walls, if not the whole wall. Where you find moisture on or inside your roof ceilings and walls, mold will grow and will lead to a wide range of health issues.
The sun with it’s UV rays is another force to be reckoned with. Whatever a roof is sealed and painted with water-resistant paint, it will be affected by UV rays. Sealing materials such as membrane and UV protective paint do not last forever. They protect your roof against the damaging effects of the UV rays of the sun and therefore needs to be replaced timeously. By not doing that you leave yourself open to much bigger expense down the line.
Insects such as Carpenter Bees and termites, to name but a few, eats away at the wood structure, weakening your it which will lead to collapse.
Repairs as an ongoing process.
Because of the nature of things, roof repairs and maintenance must always be done. Unfortunately, your roof will not last forever, therefore you should keep your hand on it and have repairs done even before things get out of hand.
Repairs can consist of the following.
As I said before you have to attend to your roof on a regular basis. Best will be if you could do seasonal maintenance. Inspect it before every season.
When Spring comes, make sure that your roof is clean of all dust, old leaves and seeds. Make sure your gutters, leave catchers and down pipes are free of debris. Water must be able to flow freely from your roof. Inspect for any visual signs of deterioration and act thereon.
Before Summer you must cut away any broken branches and branches that may cause damage to your roof. Check for broken tiles, rusting zinc sheets and any other signs of a leaking roof or standing water.
Fall is the time when you will find that trees are shedding leaves. Make sure your leave catchers are working properly. Check the roof to see that it’s up to scratch.
Winter for some places means rain, other snow and some places you have a late shedding of leaves. [Photo of snow on a roof] In the case of regions where it rains during winter you must clean your gutters, leave catchers and down pipes of debris. Where you have snow during winter make sure your roof is free of debris. Snow has quite a wait if it accumulates on your roof and can cause your roof to collapse. Clean it off regularly. Inspect your roof to see if it’s free of signs of deterioration.
1.3 Parts of a roof.
Roofs generally consist of these underlying parts.
-Roof trusses (From Wikipedia)
A truss is an assembly of beams or other elements that creates a rigid structure. In engineering, a truss is a structure that “consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object”. A “two-force member” is a structural component where force is applied to only two points. Although this rigorous definition allows the members to have any shape connected in any stable configuration, trusses typically comprise five or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes.
In this typical context, external forces and reactions to those forces are considered to act only at the nodes and result in forces in the members that are tensile . For straight members, moments (torques) are explicitly excluded because, and only because, all the joints in a truss are treated as re-volutes, as is necessary for the links to be two-force members.
A planar truss is one where all members and nodes lie within a two-dimensional plane, while a space truss has members and nodes that extend into three dimensions. The top beams in a truss are called top chords and are typically in compression, the bottom beams are called bottom chords, and are typically in tension. The interior beams are called webs, and the areas inside the webs are called panels, or from graphic statics polygons.
-Decking (or sheathing) (From Wikipedia)
In architecture, a deck is a flat surface capable of supporting weight, similar to a floor, but typically constructed outdoors, often elevated from the ground, and usually connected to a building. The term is a generalization of decks as found on ships. The decking closes and reinforces the roof structure and provides a nail bed for the shingles.
-Roof edge (or eaves edge)(From Wikipedia)
All the boards running along the edge of the roof or eaves. Also known as fascia.
Fascia is an architectural term for a vertical frieze or band under a roof edge, or which forms the outer surface of a cornice, visible to an observer.
Typically consisting of a wooden board, PVC or non-corrosive sheet metal, many of the non-domestic fascias made of stone form an ornately carved or pieced together cornice, in which case the term fascia is rarely used.
The word fascia derives from Latin fascia meaning “band, bandage, ribbon, swathe”. The term is also used, although less commonly, for other such band-like surfaces like a wide, flat trim strip around a doorway, different and separate from the wall surface.
The horizontal “fascia board” which caps the end of rafters outside a building may be used to hold the rain gutter. The finished surface below the fascia and rafters is called the offsite or eave.
In classical architecture, the fascia is the plain, wide band (or bands) that make up the architrave section of the entablature, directly above the columns. The gutter or drip edge was mounted on the fascia in the Doric order, below the triglyph. The term fascia can also refer to the flat strip below the cymatium.
-Attic (From Wikipedia)
The space under the roof. The attic must be ventilated to protect the roofing system against excessive heat in summer and warm moist air generated by the house in winter.
An attic (sometimes referred to as a loft) is a space found directly below the pitched roof of a house or other building; an attic may also be called a sky parlor or a garret. Because attics fill the space between the ceiling of the top floor of a building and the slanted roof, they are known for being awkwardly shaped spaces with exposed rafters and difficult-to-reach corners.
While some attics are converted into bedrooms, home offices, or attic apartments complete with windows and staircases, most remain difficult to access (and are usually entered using a loft hatch and ladder). Attics are generally used for storage, though they can also help control temperatures in a house by providing a large mass of slowly moving air.
The hot air rising from the lower floors of a building is often retained in attics, further compounding their reputation as inhospitable environments. However, in recent years attics have been insulated to help decrease heating costs, since, on average, un-insulated attics account for 15 percent of the total energy loss in average houses.
A loft is also the uppermost space in a building but is distinguished from an attic in that an attic typically constitutes an entire floor of the building, while a loft covers only a few rooms, leaving one or more sides open to the lower floor.
This is a structure located behind a chimney on the higher side with the function to divert rainwater around it.
The ridge of a roof is the cover at the top of the roof. This brings the two sides of the roof together and seals off the top to make it waterproof.
Where two slopes of a roof meet a V-cut piece of roofing material is inserted called a valley.
-Underlay membrane (From Wikipedia)
This coating, made of felt saturated with asphalt or a synthetic fabric, protects the shingles against resin released by the wood decking and protects the decking itself against bad weather. Ice damming on roofs: zero tolerance!
Underlay is the term for the material under roofing tiles; this roofing membrane is often made of rubber and is used to seal the roof and prevent leakage. Underlayment used with roofing shingles provides a second layer of waterproofing to prevent leaks and is called tar paper, roofing felt, or since the 1990’s synthetic underlayment.
A protective membrane that goes under some or all of the asphalt shingles.This prevents water infiltration caused by ice dams in winter.
It can be an enclosed structures made of metal or plastic feature openings and fins, four open sides and rise above the roof. One also gets a fan type, normally used on factory roofs, which is most effectively used on domestic roofs also. Both types ensure proper ventilation in the attic area. The fan-like vents make use of wind, which can blow from any direction, to produce a suction effect. This extract the hot ear from the attic.
-Plumbing vent (From Wikipedia)
In modern plumbing, a drain-waste-vent is part of a system that allows air to enter a plumbing system to maintain proper air pressure to enable the removal of sewage and grey water from a dwelling. Waste is produced at fixtures such as toilets, sinks, and showers. As the water runs down, proper venting is required to avoid a vacuum from being created. As the water runs down air must be allowed into the waste pipe either through a roof vent, or the “drain waste vent”.
-Flashing (joint covers)(From Wikipedia)
Flashing refers to thin pieces of impervious material installed to prevent the passage of water into a structure from a joint or as part of a weather resistant barrier system. In modern buildings, flashing is intended to decrease water penetration at objects such as chimneys, vent pipes, walls, windows and door openings to make buildings more durable and to reduce indoor mold problems. Metal flashing materials include lead, aluminium, copper, stainless steel, zinc alloy, and other materials.
-Shingles (From Wikipedia)
Made of fibreglass and asphalt, shingles protect the roof from rain and lend a house character.
Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat, rectangular shapes laid in courses from the bottom edge of the roof up, with each successive course overlapping the joints below. Shingles are made of various materials such as wood, slate, flagstone, metal, plastic, and composite materials such as fibre cement and asphalt shingles. Ceramic roof tiles, which still dominate in Europe and some parts of Asia, are still usually called tiles. Roof shingles may deteriorate faster and need to repel more water than wall shingles.
The minimum standards to comply with will determine your roof type. When the South African National Building Regulations were updated by the Department of Trade and Industry in May 2008, the General Requirement relating to Roofs was changed to incorporate certain safety elements.
For example, instead of simply having to “resist any forces” to which the roof might be subjected to, the regulations now state that “The roof of any building shall be so designed and constructed that it safely sustains any actions which can reasonably be expected to occur and in such a manner that any local damage (including cracking) or deformation do not compromise its functioning”.
In simple language, if there is a major wind or some other really horrible weather conditions, the roofs of our homes are expected to be able to stay on the house and protect us from the elements without themselves being damaged.
Instead of simply being “durable and waterproof”, roofs are expected to be “durable” and should not allow “the penetration of rainwater or any other surface water to its interior”.
As previously, roofs must “not allow the accumulation of any water” (but not simply rainwater, which was the limit of the old building regulations) “upon its surface”. In addition, the roof should be “adequately anchored against wind uplift” which was not covered in the previous edition of the rigs.
Lastly, the General Requirements specify (as they did previously), that the roof should be designed “as part of a roof and ceiling assembly” and should provide “adequate height in any room immediately below such assembly”. This last one, though, is open to interpretation as not all roofs incorporate ceilings as such. Read more here.
General Rules for the Construction of Roofs is available on the South African National Standards 10400 site. You will find them here.
1.5 Roof types
Roofs come in all shapes and forms, ranging from “flat” concrete roofs to steeply pitched roofs. Some roofs are tiled while others types of roofing is finished with sheeting of various types. Thatch is also used for roofing, though the structure of rafters and beams is completely different to that used for other types of roofs. Read more Here.
As far as roofs are concerned, these are the basic types.
– Flat roof
If the slope is less than 2/12, the roof is considered flat. In this case, the ratio of ventilation openings to an insulated ceiling should be at least 1:150.
– A roof without attic (often called “cathedral ceiling”)
A roof without an attic should have a 1:150 ventilation ratio. The openings should run along the base and peak of the roof.
– Roof with dormer windows (gable roof)
An attic with dormer windows leaves less room for offset. As a result, offset that allow for higher air intake (i.e., with larger perforations) should be used.
– Mansard roof (or gambrel roof)
The lower part of the roof does not need to be ventilated. However, the attic section should be ventilated according to the same standards as those for ordinary attic roofs.
– Asymmetrical roof
To balance the air intake at the top of a roof with asymmetrical slopes, the percentage of ventilation openings along the base of the longer side should be increased and those along the base of the shorter side decreased.
The SANS have useful standards that we have adapted for ease of reference. The three below specify:
1)The minimum roof slopes of sheeted roofs
2)The minimum roof slopes of non-sheeted roofs
3)The minimum thickness of thatch layers
If metal roof tiles are used on an existing roof of this category, the existing slope may be retained. But is is important to be aware that if there are strong gusts of wind, the suction force on the roof tiles might exceed the mass of the tiles.
If the tiles are securely fixed it will usually prevent them from being lifted. But a much better option is to include an underlay membrane under the slates or tiles.
This will reduce the risk of wind uplift because it can lower these pressures substantially.
NOTE: SANS 10062 contains fixing instructions for the fixing of different types of roofing. This national standard is available from the SABS.
The pitch indicated in Tables 1 and 2 are minimums. In addition to these, sheeted roofs in category 1 buildings that don’t have hips and valleys, may have a slope of 5 degrees, as long as all the end laps are sealed and have a lap of at least 250 mm. The slope of any valleys in the roof should then be no less than 11 degrees.
If tiles are laid at a pitch of 30 degrees they must (in terms of the SANS) be tested in a rig as specified in SANS 542.
The relative humidity must be maintained at a minimum of 70% during the test, and droplets should not form on the underside of the roof. It is a little different for category 1 buildings – rather than droplets forming (or rather not forming) – the test must show that water doesn’t flow down the inside of the tiles. In other words the roof MUST be waterproof!
Sheeted roofs should be tested in accordance with ASTM E 1646 to check that they don’t leak. There must be no dripping of water onto the ceiling or floor of category 1 buildings.
All tiled and sheeted roof coverings must be installed in accordance with the manufacturer’s instructions and/or by workers with the correct skills.
Thatched roofs should be installed according to SANS 10407. The required thickness of the thatch is shown in Table 3 (above).
All roofs with a pitch less than 26 degrees or more than 45 degrees, and all roofs in coastal areas (to a distance of 30 km from the sea) should have an undertile membrane that is loose-laid so that water can drain between the rafters.
If an undertile membrane is properly laid it will provide a very effective, impermeable barrier against wind-driven rain and dust. For this reason the SANS states that underlays should be provided for all slate and tiled roofs, no matter what the pitch (or slope), and where ceilings are not installed.
The manufacturers’ instructions must be followed carefully for tiles, slates and shingles.
1.7 Roof upkeep
To ensure that your roof will serve it’s purpose you need to do the following tasks regularly.
1) Keep the roof debris free. The accumulation of leaves and dust will leads to damp places on your roof. This will cause rust and mold forming and your roof will form rust spot as well as mold growth.
2) Gutters needs to be clean, free of any blockages. Water needs to be drained from the roof fast, standing water causes rust and the growth of mold.
3) Repair any small leaks or replace cracked roof tiles as soon as possible. A leaking roof, even very small holes, will damage your ceilings and cost you money.
4) Repair your roof where you see standing water. Pools of standing water on your roof will safer in and cause expensive damages.
5) Fasteners on your roof are lose. Lose fasteners causes water entry and your roof may be blown off by the wind.
6) Check for rotten beams in your roof. Beams leans to the strength of your roof’s construction. When rotten it may lead to the collapse of the structure.
7) Make sure all fascia boards in place. Fascia boards protects the side of your roof against the rain. the lack thereof will lead to water entering your roof and causes expensive replacement costs down the line
8) Check for membranes that are crack or otherwise damaged. Cracked/damaged membrane do need to be remove and replaced, if not, you will experience rain damage on your roof. That will cost you dearly.
9) Be on the lookout for broken, cracked or missing tiles. When these tiles are not replaced you will have to pay more for repairs later on.
10) Check for insufficient nock and valleys. This will cause for water that are not drained fast enough. Standing or slow moving runoff will cause water to enter your roof which will lead to a big expense on repairs later.
1.8 How to repair your roof
It all depends on the damage that needs to be repaired. the following are the most common repairs that need to be addressed on your roof. Of cause it will be best for it to be done by a professional, a person that’s trained and does this for a living.
– Zinc roofs (flat or standing)
In the case of zinc top roofs.
Rusted zinc sheets are the result of poor or no maintenance on your roof for a long time. Given time the zinc sheets will rust through and therefor fail in its task to keep the rain out.
Most times you will get away with removing the surface rust and apply a layer rust repellent before painting with a proper roof paint. However, this is a short term resolution because the rust will return in a couple of months.
It will serve you well if the zinc sheets are replaced altogether. Best to use the services of a professional. Not only will the task be done correctly but you will have the peace of mind that your belongings and family will stay dry and be protected against the weather.
Water standing on your roof has the risk of moisture seeping in as well as dust accumulation which will promote rust and mold growth. This leads to the failure of your roof.
Get a specialist to inspect and repair the damaged area.
Fasteners, which holds the zinc sheeting tight to the beams, do come loos in time as a result of expansion and shrinkage as well as the wind tacking on the zinc sheets. This leads to openings where water will enter your roof and will cause the rotting of the wooden beams.
A professional will advise you best as to replacing the fasteners and properly sealing the potential water leaks.
Even if these beams are properly treated, water and nature do attack them. Nature, in the form of insects, loves and has the ability to break down wood to be re-used by nature. Wood that is attacked like this weakens and will fail.
The replacement of damaged roof structure is advised. In order to get to the damaged area and replace it, all covering material needs to be removed. This is very labor intensive and you are advised to call in the specialists.
5)Missing fascia boards
The reason for facia boards is to protect the side of your roof. Just like fasteners on the top of your holding down zinc sheets, facia boards are held by screws or nails. These do come to lose over time. Fix the facia boards properly to your roof.
The UV light from the sun does break down the membranes over time (nothing lasts forever). You will typically find these membranes where the roof meets a side wall or a chimney.
Remove the damaged membranes and replace with fresh ones.
– Tile roofs
1)Broken/cracked or missing tiles
Tiles do damage from time to time. Inspect your roof regularly for those damaged tiles. Replace them as soon as possible.
2)Insufficient peaks and valleys
With insufficient nock and valleys there will insufficient flow of water. Then water can not be removed from a rooftop it will enter the roof and damage it. Mold will grow where there is moisture and that will lead to illnesses. Have your roof be inspected and corrected.
Membranes are placed where the roof tiles meet a wall or other structure on the roof like a chimney. These membranes should be replaced when found to be damaged.
– Concrete roofs
Lookout for standing water on your concrete roof because it will lead to damage and mold growth. Damaged concrete will lend to the failure of the roof as well as mold growth with cost effects in the future. Have your roof’s runoff corrected and then sealed again.
Cracks happened when concrete expands and contracts during day and night time. When cracks are found they must be attended to as soon as possible. Have the cracks filled and then have the concrete sealed.
Rubber mats and asphalt does not last forever. Inspect the rubber mats and have them replaced if needed.
Waterproofing roofs are perhaps the most important factor when it comes to roof construction.
The National Building Regulations and Building Standards Act state that roofs must be designed and constructed safely so that they are not damaged by wind or any other natural force. The law also states that they must be waterproof, specifically:
-Roofs must be durable and must not allow the penetration of rainwater or any other surface water to its interior.
-Roofs must not allow the accumulation of any water on its surface.
But the legislation simply lays down the basics. For additional guidance, anyone building needs to refer to the South African National Standard that explains how the law can be successfully applied.
In terms of waterproofing, the Standard, The application of the National Building Regulations Part L-Roofs specifically covers:
-Roof coverings and waterproofing systems, and
-Drainage and waterproofing of flat roofs.
The SANS elaborates on the legislation stating that roofs must be able to resist the penetration of rain to the extent that water in category 1 buildings (see below) any water that penetrates the roof won’t run down the inside face of walls onto the floor or form damp patches on the ceiling or the floor. In terms of all other buildings (i.e. those that are not category
1), if water penetrates the roof it won’t be intense enough to run down the inside surface of the roof or drip onto the floor or ceiling.
The SANS also states those roof coverings and waterproofing systems must be capable of being repaired if damaged, even if the materials are old.
In addition, roof coverings must be able to resist:
-temperatures from -10 degrees C to +80 degrees C, as well as quick changes of temperature, without deteriorating
-the effect of UV radiation, without deterioration
-effects of condensation under the surface
-chemical attack from basic salt or gas in the atmosphere
-growth of bacteria, fungi, lichens and so on
-any penetration or puncturing while the roof is in use
-movement of the roof structure
All products that are used for roof coverings and waterproofing systems must have a lifespan of at least 10 years. If the structure or system is particularly intricate, making it difficult to replace, then the expectation is that materials used should have a lifespan of at least 20 years.
Flat roofs can be extremely difficult to waterproof, which is why all so-called “flat” roofs should be built with a fall of 1:80. This might require a steeper design slope of 1:50 in concrete slabs where construction is not always 100% accurate. A 1:50 slope is also required where there is an interruption in the flow of water on the roof.
The slope should be towards external gutters, roof edges and outlets. Other factors that should be considered include:
-an avoidance of “penetrations” through the roof or they should be at least 200 mm away from vertical surfaces like walls and “upstand” beams
-avoidance of having clusters of plumbing pipes, air conditioning pipes, and electrical conduit
-formation of a suitable step between inside and outside areas to prevent water flowing or dripping into the interior of the house or other building
It is very important that precast panels and precast roof structures are designed in a way that if there is the subsequent movement of the concrete elements, this will not damage the waterproofing system or compromise its performance.
The SANS has a really useful drawing that shows how construction drawings should clearly designate ridges and valleys and indicate the relative fall – or slope.
Any concrete roof design should take the thermal properties of concrete into account. This will be determined by a concrete technologist or another competent person, who will determine the required thickness of the concrete and its density, and design the roof in such a way that a waterproofing layer is built up.
Often the designer will incorporate a “thermally insulating layer” above the structural concrete deck. When this is done it is important that attention is given to ventilation so that any moist air that might accumulate below the waterproofing layer is vented to the outside.
The concrete used for flat roofs shouldn’t contain more than 7% moisture by weight, and sand-cement or lightweight screeds shouldn’t contain more than 10% moisture by weight.
If expansion joints to accommodate the flow of water are not custom-designed by a competent person, “twin kern upstand-type joints” should be installed over any expansion joints. These should be positioned away from any outlets and should be built in accordance with the illustration given in SANS 10400-L.
Upstand beams that are at least 170 mm high should be incorporated where masonry walls meet the concrete surface of the roof. At these “intersections” (i.e. where they join) corner fillets measuring at least 75 mm (vertically and horizontally) should be built-in. There is another drawing in the SANS that shows how this should be done. Another drawing shows how drips should be incorporated under all overhangs of concrete roofs.
In addition to these design elements, all concrete and screened roof surfaces must be waterproofed and constructed to the correct falls and cross falls (see the first paragraph under Drainage and Waterproofing of Flat Roofs above and the relevant section in the SANS). It is vital that there are no undulations in the concrete surface, and nothing should be allowed to protrude into the concrete or contaminate it.
The recommended finish for concrete roofs is wood floating. While the final surface should be sound and smooth, concrete and screened surfaces should not be highly polished. So they should NOT be power floated.
Any waterproofing system that is installed on flat roofs MUST be done by a “competent person” who MUST follow the manufacturer’s instructions. SANS 10400-L states that for roofs to be up to standard, they must remain watertight for at least five years without the need for any form of maintenance other than the normal cleaning of down pipes, gutters and so on.
It is also important that the person doing the installation is satisfied that the materials used are appropriate for that particular application, and should, therefore, take into account:
-the degree of exposure the waterproofing system will be subjected to
-how much protection the waterproofing material will have
-and ultimately whatever affects the building because of where it is located
It is important to realize that waterproofing systems can de-laminate if the substrates don’t allow any moisture vapor that has been trapped to escape. Generally, a sand-cement screed that is not very dense will allow retained moisture vapor to dissipate and therefore protect against the possibility of de-lamination.
SANS 10400-L suggests that a 20 mm screed is laid over all “lightweight” screeds because these are generally too friable and porous to provide good adhesion for waterproofing systems. The SANS also suggests that concrete and screened roof surfaces be allowed to dry thoroughly before any type of waterproofing system is applied.
Where waterproofing turnups are provided against brickwork and other masonry walls, they should be counter-flashed if they are not linked to the stepped damp-proof courses in cavity walls. The same membrane should be used, and the flashing should be cut into walls to a depth of at least 40 mm.
Generally, sand-cement coves with a radius of at least 45 mm should be formed at all the inside corners of both vertical and horizontal surfaces – unless a particular waterproofing system has a different design and doesn’t require this. Where there is a timber deck, 38 mm timber fillets may be fixed at all the junctions of horizontal and vertical surfaces.
There is always a potential problem with outlets. The installer must, therefore, pay close attention to overflow pipes, flues and so on, and make sure that the waterproofing material used covers everything but the opening. Generally, waterproofing membranes around any pipework should be clamped with a hose clamp or something similar, before the flashing is applied over the pipe.
If outlets aren’t the “full-bore”, coned type, pipes should be flanged so that waterproofing can be done correctly. Elements such as water storage tanks and solar absorbents should never be allowed to penetrate the waterproof layer.
All external corners and edges to be waterproofed should be rounded, and the height of all DPCs should be at the same level as the waterproofing turnups.
In addition to this part of SANS 10400, SANS 10021 also provides some information and guidance about the waterproofing of roofs. Remember, it’s important to do it correctly!
Gutters and down pipes are not mandatory. However, unless gutters are designed by a competent person, they may only be located on the “perimeter” of the building. They should also be designed to ensure that storm water doesn’t penetrate the inside of any building if they become blocked at any stage.
Rain chains are a popular alternative option to down pipes from gutters
Outlets must be set flush with the concrete. If there is timber decking they must be recessed so that there isn’t any water standing around the outlets. Any outlets should be at least 500 mm from upstand elements including parapet walls, and they should be at least one metre from any expansion joints.
Installation requirements of manufacturers and suppliers of rainwater goods absolutely must be adhered to.
3.1 Introduction (From Wikipedia)
Paint is any pigmented liquid, liquefiable, or mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture to objects. Paint can be made or purchased in many colors—and in many different types, such as watercolor or synthetic. Paint is typically stored, sold, and applied as a liquid, but most types dry into a solid. Most paints are either oil-based or water-based and each has distinct characteristics.
For one, it is illegal in most municipalities to discard oil-based paint down household drains or sewers. Solvents for clean up are also different for water-based paint than they are for oil-based paint. Water-based paints and oil-based paints will cure differently based on the outside ambient temperature of the object being painted (such as a house.)
Usually, the object being painted must be over 10 °C (50 °F), although some manufacturers of external paints/primers claim they can be applied when temperatures are as low as 2 °C (35 °F)
3.2 Roof painting (From Wikipedia)
A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. Many roof coatings are elastomeric, that is, they have elastic properties that allow them to stretch and return to their original shape without damage.
Typical roof coating dry film thickness vary from paint film thickness (plus or minus 0.075 mm (3 dry mils) to more than 1 mm (40 dry mils). This means a roof coating actually becomes the top layer of a composite roof membrane and underlying system.
As such, the roof coating is the topmost layer of protection for the membrane, receiving the impact of sunlight (both infrared and ultraviolet (UV), rain, hail and physical damage.
Roof Coatings should not be confused with deck coatings. Deck coatings are traffic bearing – designed for waterproofing areas where pedestrian (and in some cases vehicular) traffic is expected. Roof coatings will only waterproof the substrates but will not withstand any kind of ongoing use by people.
Different applications for different roofs. Zinc roof tile roof concrete roof.
3.3 Interior painting [LINK]
Interior paint is made to be scrubbed, resist staining, and allow cleaning.
The wide variety of interior paints can be bewildering — but they exist for a reason. The trick is to be knowledgeable about their respective uses and strengths. Because there are such differences between the many paints, it’s important to know about each kind.
Although interior paints are available for every possible surface, there is no such thing as an all-surface paint. The wrong paint can damage a surface and often not adhere well, so it’s crucial to know in advance what goes where and when. Fortunately, modern paint technology has taken a lot of the risk out of choosing the proper paint.
Formulas for so-called “latex paints” have been improved to withstand dirt, moisture, and daily wear and tear, so these paints are no longer reserved exclusively for low-traffic areas. They are as washable and durable as the old oil base paints, so you no longer have to think in terms of latex paints for walls and oil base enamels for woodwork, windows, and doors.
Still, an important factor in interior paint selection — aside from personal color preference — is gloss. Regardless of the type of coating you choose, the gloss of the one you buy will affect both its appearance and its durability. High-gloss paints are the most durable because they contain more resin than either semigloss or flat paints. Resin is an ingredient that hardens as the paint dries. The more resin, the harder the surface.
Consequently, for kitchens, bathrooms, utility rooms, doors, windows, and trim, high-gloss paints are ideal. Semigloss interior paints, with less resin and a reduced surface shine, are slightly less wear-resistant but still suitable for most woodwork.
Finally, flat paints are the coatings of choice for most interior walls and ceilings because they provide an attractive, low-glare finish for surfaces that take little abuse and require only infrequent washings.
3.4 Exterior painting [LINK]
Exterior paints are made to combat against fading and mildew.
Choosing exterior paints can be complicated because of the wide range of surfaces. These surfaces include clapboard and aluminium siding, wood shingles, tar shingles, cedar shakes, brick, concrete block, stucco, and, of course, old paint. On many older homes, you’ll find a combination of these surfaces. Fortunately, there is an exterior paint for every type of surface, and some paints are suitable for more than one surface.
Like interior paints, exterior paints are available in either water-thinned or solvent-thinned formulas and in three lustres: flat, semigloss, and gloss. There are, however, several characteristics that distinguish exterior paints from those used inside the house. For one thing, exterior paints are more expensive.
They also contain more resin (for moisture resistance and durability) and more pigment (for color).
You may want to choose your exterior paint based on what was used before. As with interior paints, latex works best over latex and alkyd works best over alkyd. If you can’t tell or are unsure about what type of paint is on the house, use alkyd-base paint.
Latex exterior paints are easier to apply, dry quickly, and can help minimize moisture problems because they “breathe.” Cleaning up is a matter of soap and water. These paints do not adhere as well to oil-base or alkyd-base paints or too poorly prepared surfaces, however.
Alkyds, on the other hand, are extremely durable, but they are more difficult to work with and they dry slowly. Also, solvents must be used with alkyds to clean brushes, rollers, paint trays, and drips.
One of the alkyd types of exterior paint may be especially appealing because of its regulated, self-cleaning property. It’s called “chalking,” and that’s exactly what it does. Over a period of years, the paint surface slowly oxidizes. Each rainfall washes off a minute quantity of the paint — along with dirt.
As a result of this shedding, the paint surface is constantly renewing itself. The price of this convenience used to be chalky residue on foundations and shrubs, but the newest formulas control the shedding so it doesn’t stain adjacent surfaces.
Chalking paint is not recommended for every house. In areas with little rainfall, for example, the powder tends to remain on the surface, dulling the paint. In wet regions, chalking paint may not be worth the extra expense because frequent rainfalls will keep the outside of the house clean no matter what kind of paint is used.
If you live in or near either of these climatic extremes, ask your paint dealer if the chalking type is suitable for your area.
Tremco provides a complete maintenance solution for your home (except for electrical and plumbing works). This roof repair, waterproofing and the painting contractor have 30 years of experience in (a) roof repair, (b) waterproofing roofs and walls as well as (c) painting of roofs, interior- and exterior walls.