Building Facts & Advice
Straight answers to common building questions in the Western Cape - from building near the sea and getting your plans approved, to choosing the right cement, timber and paint. Questions we haven't answered? Call us on 028 435 6331 or WhatsApp 076 370 4367.
Bathroom & Kitchen
Who may install or replace a geyser?
Fixed electric geysers must be installed according to SANS 10254 and the plumbing must be signed off by a registered plumber, who issues a certificate of compliance. Many insurers will only pay a geyser claim if the installation complies, so use a registered plumber.
Solar geyser or heat pump - which is better?
Both cut electricity use for hot water. A solar geyser uses free sunshine and works well in the sunny Western Cape, while a heat pump uses a small amount of electricity to heat water efficiently day or night and needs less roof space. For new homes, SANS 10400-XA requires at least half of hot water to come from something other than electric resistance heating.
Can I reuse grey water in the garden?
Grey water from showers, baths and washing machines can be used to water the garden if you follow your municipality's guidelines - use it soon after collection, avoid water with harsh chemicals, and do not let it pool or run onto neighbouring properties. Toilet (black) water must always go to the sewer or septic system.
What causes low water pressure in a house?
Common causes are a partly closed stopcock, a blocked filter or aerator, old corroded galvanised pipes, a faulty pressure-reducing valve, or a geyser problem. In some towns low municipal pressure is the cause, and a booster pump can help.
Building & Construction
Which cement should I use: 42.5 or 32.5?
Higher-strength cement (42.5 class, for example CEM II 42.5N) is generally used for structural concrete such as foundations, slabs and columns. 32.5 class cement is commonly used for brickwork mortar and plaster. Always follow the mix on the bag or your engineer's specification.
How long must concrete cure before I load it?
Concrete keeps gaining strength for weeks. Keep it damp (covered or regularly sprayed) for at least the first 7 days, especially in hot or windy weather. It reaches most of its design strength after about 28 days - check with your engineer before heavy loading.
What is a damp-proof course and where does it go?
A damp-proof course (DPC) is a strip of plastic membrane built into the wall that stops ground moisture rising into the brickwork. It is placed in walls just above the ground and floor level - typically at least 150 mm above finished ground level - and lapped properly at joints. Without it, walls stay damp and paint and plaster fail.
Which bricks or blocks should I use?
Use face bricks or exterior-grade blocks for walls exposed to weather and plaster bricks or blocks where walls will be plastered. Cement blocks are common for boundary walls and outbuildings. Make sure the units you buy meet the relevant SANS standard and the strength your plans specify.
What do the timber treatment classes H2 to H6 mean?
Treated pine in South Africa is graded by hazard class under SANS 1288: H2 for dry indoor use (insects), H3 for outdoor use above the ground, H4 for timber in contact with the ground, H5 for fresh water, and H6 for marine use in sea water. Use at least H4 for fence posts and anything set in soil.
Why do roof trusses have to be designed?
A roof truss carries the weight of the roof covering, wind and sometimes ceilings or solar panels, so the timber sizes, joints and nail plates must be calculated for the span, pitch and roof type. HPM designs and manufactures roof trusses to your plans, so they fit your building and can be signed off with an A19.
Can I get steel or timber that is not in stock?
Yes. HPM sources steel and timber on request - send us the sizes, lengths and quantities and we will quote, including delivery.
How do I work out how many bricks or how much cement I need?
As a rough guide, a standard brick wall uses about 50 bricks per square metre for a single skin and about 100 for a double skin, plus extra for waste and breakage. Mortar and plaster quantities depend on the mix and thickness. Send us your plans or measurements and we can help you work out a materials list and quote.
Is building sand the same as plaster sand?
No. Building (brick) sand is used for mortar in brickwork, plaster sand is finer and cleaner for a smooth plaster finish, and river sand or crusher sand is used with stone in concrete. Using the wrong sand weakens the mix or causes cracking.
Do I need a steel lintel above windows and doors?
Yes - every opening in a load-bearing wall needs a lintel (precast concrete or steel) to carry the brickwork above it. The lintel size and the bearing on each side depend on the opening width and the load, as shown on your plans.
Building Regulations
Which rules apply when I build in the Western Cape?
All building work in South Africa falls under the National Building Regulations and Building Standards Act (Act 103 of 1977). The technical rules are in SANS 10400, which has parts for each topic - for example Part H (foundations), Part K (walls), Part L (roofs), Part P (drainage), Part T (fire) and Part XA (energy efficiency). Your local municipality enforces them.
Do I need approved plans before I start building?
Yes. New buildings, additions, and most structural alterations need building plans approved by your local municipality before work starts - for example Cape Agulhas Municipality for Struisbaai, Bredasdorp and L'Agulhas, Overstrand for Hermanus and Kleinmond, or the City of Cape Town. Building without approval can lead to fines, problems when you sell, and even an order to demolish.
What is an A19 form for roof trusses?
The A19 is the certificate in which a competent person (usually a registered engineer or roof truss designer) confirms that a roof truss structure was designed and erected correctly. Municipal building inspectors ask for it before they sign off a new roof. HPM designs and manufactures roof trusses and can help with the A19 compliance paperwork.
Does a new house have to be enrolled with the NHBRC?
Yes. Under the Housing Consumers Protection Measures Act, a new home must be built by a home builder registered with the National Home Builders Registration Council (NHBRC) and enrolled with the NHBRC before construction starts. The enrolment gives the owner warranty cover against major structural defects.
Which certificates do I need when I sell a house in South Africa?
The seller usually needs an Electrical Certificate of Compliance (CoC). Depending on the property, a gas CoC (for fixed gas installations), an electric fence compliance certificate, a beetle (wood borer) certificate - common in the Western Cape - and, in the City of Cape Town, a water installation certificate may also be required. Your conveyancer will confirm what applies.
What does SANS 10400-XA mean for a new home?
SANS 10400-XA sets energy efficiency rules for new buildings and additions: insulation in the roof, limits on glazing area or better glass, and at least half of the hot water must come from something other than electric resistance heating - for example a solar geyser or a heat pump. Plans must show how the house complies.
Can I put up a boundary wall without approval?
Usually not. Most municipalities in the Western Cape require approved plans for boundary walls above a set height and for walls on a street boundary, and many estates and coastal towns have extra rules about height and finish. Check with your municipality (and your estate or home owners' association) first.
Do I need permission to install grid-tied solar panels?
Yes. Western Cape municipalities require you to apply and register a small-scale embedded generation (SSEG) system, such as grid-tied solar, before it is connected, and the installation must be signed off by a registered electrician. Off-grid systems that never connect to the municipal supply still need a valid electrical CoC.
Coastal Building
How does the sea air affect building materials on the Western Cape coast?
Salt in the air speeds up corrosion of steel, fixings and roof sheeting, and it damages paint and render faster than inland. In seaside towns such as Struisbaai, L'Agulhas, Arniston, Hermanus, Mossel Bay and the Cape Town coast, choose materials made for marine or coastal conditions, and rinse exposed metal with fresh water now and then.
Which nails, screws and bolts should I use near the sea?
Use hot-dip galvanised or stainless steel fixings - grade 316 stainless is best close to the sea. Ordinary bright or electroplated fixings rust quickly in salt air and stain the surrounding paint and timber.
Can I mix stainless steel and galvanised fixings?
Avoid it. When different metals touch in damp, salty air, galvanic corrosion eats away the weaker metal - usually the galvanised part. Use one type of metal throughout a connection, or separate the metals with a washer or sleeve that does not conduct electricity.
What roof sheeting works best at the coast?
Choose sheeting with a coating rated for coastal or marine environments, such as a heavier zinc-aluminium coating with a factory-applied colour coat, and fit it with matching coastal-grade screws and washers. Wash the sheets down periodically where rain does not reach, for example under overhangs.
How do I protect my roof against strong Western Cape winds?
The south-easter in summer and the north-westerly storms in winter can lift roofs. Make sure trusses are properly tied down to the walls with straps or wire as specified by the truss designer, fix the sheeting with the right number of screws (more at edges and ridges), and keep overhangs within the design. SANS 10400-L covers roof requirements.
How often should exterior paint be redone near the sea?
Expect to repaint more often than inland because UV and salt break paint down faster. Wash walls down once or twice a year to remove salt, repair cracks before they let water in, and use a good-quality exterior paint made for harsh coastal conditions.
Electrical & Technology
Do I need an electrician for new plug points or lights?
Yes. Electrical installation work in South Africa must be done or supervised by a registered electrician, who issues a Certificate of Compliance (CoC) for the work. DIY wiring can void your insurance and is dangerous.
Why does my earth leakage keep tripping?
The earth leakage unit trips when electricity leaks to earth - often from a faulty appliance, damp in an outside plug or light, or damaged wiring. Unplug appliances and switch circuits off one at a time to find the cause, and call an electrician if it keeps tripping. Never bypass the earth leakage.
What do I need for a backup power system?
A typical home backup system has an inverter, batteries (lithium is the most common today) and, optionally, solar panels to recharge them. It must be installed by a qualified installer and signed off with an electrical CoC; grid-tied systems also need municipal registration.
Home Improvement
How long should new plaster dry before painting?
New plaster needs time to cure and dry out - often around four weeks in good weather. Paint too early and the alkaline plaster can cause the paint to fail. Prime with an alkali-resistant plaster primer before applying the top coats.
How do I stop damp on inside walls?
First find the cause: rising damp (no or broken damp-proof course), water coming through the wall from outside, leaking plumbing, or condensation from poor ventilation. Fix the source, let the wall dry, then use a suitable damp-proofing treatment and paint system. Painting over damp alone will not solve it.
Which paint should I use outside?
Use a quality exterior acrylic (water-based) paint for walls; it lets moisture escape and copes with sun and rain. For timber, use a suitable exterior varnish, sealer or enamel, and for metal use a rust-inhibiting primer first. Prepare surfaces properly - most paint failures come from poor preparation.
How do I waterproof a flat roof or a parapet wall?
Clean the surface, repair cracks, prime it, and apply a waterproofing system (liquid membrane with reinforcing fabric, or torch-on membrane) - paying special attention to joints, corners and drains. Re-inspect it every year, as most leaks start where the membrane has cracked or lifted.
What is the best way to fix cracks in walls?
Hairline cracks in plaster can be filled with a flexible crack filler and painted. Wider cracks, cracks that keep growing, or cracks that run diagonally from windows and doors may point to foundation or structural movement and should be checked by a professional before you repair them.
How do I treat wood borer (beetle) in roof timber?
Wood borer is common in older Western Cape homes and a beetle certificate is often needed when you sell. Look for small holes and fine dust on the timber. Infested timber can be treated with an approved timber insecticide or, if badly damaged, replaced with treated timber; a pest control company can issue the certificate.
Ordering & Delivery
Does HPM deliver outside Struisbaai?
Yes. Parcels up to 50 kg go anywhere in South Africa by The Courier Guy, priced live at checkout. Heavy and bulky materials such as cement, bricks, sand, stone, steel and timber are delivered with our own trucks across the Western Cape - the Overberg, Cape Town and surrounds, Boland, West Coast and Garden Route.
Is there a minimum order for truck delivery?
Truck deliveries outside Struisbaai have a minimum of 8,000 kg or R10,000 order value per delivery, and the cost is calculated at checkout from the weight and the distance from Struisbaai. In Struisbaai itself there is no minimum and truck delivery is free.
How long does delivery take?
Courier delivery times are shown at checkout and depend on your area and the service you choose. Truck deliveries are usually within 7 to 14 working days, and often sooner. You can also split an order: light items go by courier first and the heavy items follow on our truck.
How can I pay for an online order?
Online orders are paid securely through PayFast, which offers card, Instant EFT and other payment options. Approved customers can also buy on their HPM credit account, and builders and contractors can apply for a trade account.
Can I get a quote for a whole building project?
Yes. Send us your plans or a materials list and we will quote for the materials and delivery. You can also save material lists (Bou-lys) on the website and turn them into a quote or order.
Can I return building materials?
Building materials cannot be returned unless they are defective. Unwanted non-building items (tools, hardware accessories, unopened electrical items) can be returned within 7 days if unused and in the original packaging. Report shipping damage within 48 hours and defects within 14 days. See the full Returns policy on our website.
Can I order online and collect in store?
Yes. Choose "Collect from store" at checkout and collect your order free from HPM in Cinneraria Street, Struisbaai. Opening hours are Monday to Friday 07:30-17:15 and Saturday 08:00-13:00.
Outdoor & Garden
How do I protect my property against fynbos fires?
In fynbos areas such as the Overberg and Cape Peninsula, keep a cleared firebreak around buildings, remove dry vegetation and wood piles near walls, clean leaves from gutters and roofs, and keep a hose that can reach every side of the house. Thatched roofs need extra fire protection - check with your insurer and municipality.
What should I know before installing a rainwater tank?
Place the tank on a level, solid base that can carry the full weight of the water (about one ton per 1,000 litres), fit a leaf filter and first-flush diverter, cover all openings against mosquitoes, and keep tank water separate from the municipal supply. Some municipalities have rules or rebates for tanks.
How do I lay paving that will not sink?
Remove topsoil, compact a proper sub-base (usually crushed stone) in layers, add a bedding sand layer, lay the pavers with edge restraints, then compact them and brush joint sand in. Most sinking paving was laid on a poorly compacted base.
What fence posts last longest in the ground?
Use treated timber rated H4 (or higher) for posts in the ground, or galvanised steel or concrete posts. Set posts in concrete with the top of the concrete sloped away from the post so that water runs off.
Tools & Equipment
Which power tools should a DIYer buy first?
A good cordless drill/driver is the most useful first tool, followed by an angle grinder, jigsaw or circular saw depending on your projects. Staying with one battery platform saves money because the batteries and chargers can be shared across tools.
What safety gear do I need for building work?
At minimum: safety glasses, hearing protection for power tools, a dust mask (or respirator for cutting cement products), gloves, and safety boots. On a construction site, a hard hat and high-visibility vest are usually required as well.
General guidance only - building rules and approvals differ between municipalities and projects. Check with your local municipality, a registered professional or the relevant SANS standard before you build.