The Raslouw Light & Glass Field Guide

01 — Ground truth

Raslouw is mid-transformation, and its windows show it

Drive west out of central Centurion and the stands get bigger before they get smaller again. That is Raslouw: an old belt of agricultural holdings, plots and small farms — a fair share of them still standing, which keeps the suburb's open, semi-rural character^[1][2] — now being carved, estate by estate, into secure complexes such as Raslouw Lifestyle, Raslouw Glen and Raslouw Manor, on stands running from townhouse-tight to surviving smallholding.^[1]

So the housing stock splits two ways here, and both ways lead to glass. The new estate homes are drawn around one big open volume — kitchen, dining and lounge sharing a single space, stacking doors handing the whole lot to the patio. The older plots under renovation tend to gain exactly the same arrangement in the alterations. Either way, three or four openings end up doing all the work: the sun, the privacy, the entertaining.

Standard blind sizes assume standard windows, and Raslouw builds very few of those. Double-volume entrance glazing, five-metre sliders, stair-void panes, the occasional gable — these are made-to-measure openings by definition, and each deserves its own answer rather than a blanket product stretched across the house.

One more catch particular to this suburb: the estate roads curve. Two houses in the same street can point their patios at entirely different compass points, so a guide can only describe what the sun does over Raslouw — a compass held flat against your own wall is what says what it does to your lounge. That reading is part of the free measure, at the end of this page.

02 — The geometry

The numbers behind a Raslouw afternoon

Two coordinates set everything else. Centurion lies at about 25.86° south and roughly 1,450 m up on the Highveld plateau.^[3] The nearest rigorous sun-geometry study in the South African planning literature is computed for Pretoria at 25.733° south^[4] — close enough that this page treats its figures as Raslouw's own.

Midday on 21 December, the sun stands at 87.7° — to the eye, directly overhead. Midday on 20 June, it manages 40.84°.^[4] Nearly forty-seven degrees separate the two readings, and that gap is the honest reason one fixed product seldom serves a room all year: the blind that tames a vertical December sun is not the blind that welcomes a slanting June one.

Where the sun goes down moves just as far. December sunsets land at an azimuth of 243.35°, well south of due west; June's at 295.76°, well north of it.^[4] Across a year the setting sun works along fifty-two degrees of your western horizon, so a fixed overhang or patio roof tuned to one month's sunset simply misses another's.

The study's practical findings line up with what we see on installations: afternoons on west glass run significantly hotter than mornings ever do on east glass; horizontal overhangs do their best work against the high northern sun; and the low sun east and west needs something vertical standing in its path.^[4]

Altitudes and sunset bearings from the published Pretoria dataset at 25.733° S^[4]; Raslouw sits about a tenth of a degree further south.

Three Highveld conditions your blinds will live with

Altitude sharpens the UV. Thinner air at ~1,450 m^[3] filters less ultraviolet — the level climbs about 12% for every 1,000 m of height.^[5] Cheap dyed fabric on a west window fades visibly within a few Raslouw summers; on the sun side, specify by fabric performance and let colour come second.
The storm hour is documented — and so is the hail season. Summer rain arrives as fast afternoon convection over the Highveld,^[7] and the satellite record for Gauteng puts peak hail in the first half of November, most often between 16:00 and 17:00.^[6] Anything that lives on the outside of your wall needs a plan for that hour; ours is a wind sensor, fitted as standard.
July is the other design problem. Winters here are dry and clear with frost-cold nights,^[7] which turns big panes into heat leaks. A blind's still-air layer earns its money in July in a way nobody thinks about in January — insulating value belongs in the spec alongside shading value.

03 — The compass walk

Four walls, four different jobs

Product comes second; the wall comes first. Here is the short version of what each elevation of a Raslouw house asks for — the rule we apply before we talk fabric at all.

North — the wall that pays you back

North glass is the one elevation in a Raslouw house that earns its keep in July. At the June solstice the noon sun sits at just under 41°, low enough to push light and warmth deep into the room; in December it climbs to nearly 88°, high enough that a normal estate-house overhang is already doing the shading for you.^[4] Treat this wall as permanently opaque and you are throwing away heating you never have to pay for.

Our rule: nothing goes on a north window unless it can be tilted open or pulled right out of the way.

West — the one that empties the room

From roughly three in the afternoon the sun arrives almost flat, and it does not arrive from the same place twice: the setting bearing wanders across fifty-two degrees between December and June.^[4] Awkwardly, on most Raslouw plans this is the side that carries the patio and the view. There is also a physics problem buried in it — glass that has been cooking all afternoon keeps radiating into the room long after the glare has stopped, so a blind hung on the inside deals with brightness at once and with temperature only in part.

Verdict: intercept it outside the pane where the budget stretches; a serious sunscreen fabric where it doesn't.

East — early light on a cold house

West's geometry run backwards, into rooms that have been shedding heat all night. Midsummer sunrise here is early and comes in under everything; on the tighter stands of a boomed complex it clears the neighbour's roofline and lands square on a bedroom window before six. The complication is that one east wall usually serves two rooms with opposite briefs — a bedroom that wants genuine darkness, a breakfast corner that wants the garden.

Verdict: specify this wall for sleep and glare. Heat is not the argument here.

South — steady light, cold glass

Direct sun barely touches this side for most of the year, which gives south rooms the calmest and most even light in the house — the reason so many home offices end up here. It also makes them the first to go cold once a clear, dry Highveld night sets in.^[7] The brief on a south window is hardly ever about blocking sun; it is about what leaves through the glass after dark.

Verdict: specify for insulation. Shading is the bonus, not the job.

Optional

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Name the rooms giving you grief. We'll send this guide back with notes written into it — the order we would tackle your openings in, and the argument we'd be having with ourselves on each one.

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04 — The specification

What we'd fit in Raslouw, and the catch with each

Every product below is the correct answer in one part of an estate home and the wrong one in another. So each entry gets a plain description, then the paragraph a supplier's brochure leaves out: where it lets you down. Tap "Add to my list" while you read and it lands in the window list and the measure form at the foot of the page.

Sunscreen roller blinds

Patio- & garden-facing living glass

An open-weave fabric, woven tightly enough to knock down glare and a worthwhile slice of the heat, running as one flat sheet on a slim tube. No folds, no gathers, nothing to shake dust out of. What it buys you is the thing a lined curtain destroys: at four in the afternoon you still have your garden, your patio and your lawn, which is presumably why the architect put five metres of glass there.

The trade-off

The whole effect inverts at sunset. Lamps on inside, and the fabric that hid you all day now frames you. Where a neighbouring stand sits close — common enough in the tighter Raslouw complexes — we run a blockout on the same bracket set and you pick one for the evening.

Blockout roller blinds

Bedrooms · east elevations

Same mechanism, opaque cloth. It does two jobs at once that people tend to think of separately: it takes an early east sunrise out of a bedroom, and on a frosty July night it puts a still layer of air between you and a cold pane. If a room has to be genuinely dark, this is where the conversation starts.

The trade-off

There is no middle setting. Down is night, up is full daylight, which makes it exactly the wrong instrument in a north-facing lounge where the June sun is an asset. And light is stubborn: without side channels it will find its way round the edge of the reveal and draw a bright line on your wall at dawn.

Day & night blinds

Open-plan living areas

Two layers of banded fabric on one tube. Slide them and the sheer stripes line up with the solid ones or slip between them, so a single blind moves smoothly from clear view to closed. The reason it suits Raslouw specifically: an open-plan kitchen-dining-lounge is one room facing several ways, and the light in it changes character three or four times before supper. This is the product that follows that without you having to think about it.

The trade-off

Two honest limits. The sheer bands are still sheer, so evening privacy means closing right up. And on a genuinely punished west wall it is outclassed — this is a light-control product that helps a little with heat, not a heat product that helps a little with light.

Timber & aluminium venetian blinds

North rooms · sculleries · bathrooms

Here is the argument for slats. On a north wall the sun swings through forty-seven degrees of altitude between the solstices,^[4] and what you want to change through the year is the angle of the barrier, not how much of the window it covers. Tilt the slats and a high December sun bounces off them onto the ceiling; open them flat and the low June sun walks straight in. One product, both ends of the swing — which a roller simply cannot do. Timber reads warm in a lounge or study. Aluminium is the one to put in the scullery, the laundry and the guest bathroom, where steam would eventually warp anything wooden.

The trade-off

Dust. A slatted blind has many more edges than a flat sheet and takes correspondingly longer to clean, which matters on a wide north window with twenty-odd slats across it. Aluminium wipes down in a fraction of the time timber takes — factor that in before you choose on looks alone.

Cellular / honeycomb blinds

Nurseries · south rooms · studies

The fabric is folded into rows of sealed cells, and each cell traps a pocket of still air against the pane. Still air is a poor conductor — that is the entire trick, and it is why this is both the best-insulating and the quietest fabric blind we hang. Put it on a south room, a nursery or a study that goes cold on a clear Highveld night^[7] and you have bought most of the benefit of better glazing for a small fraction of the cost. Cordless operation comes as standard, which settles the child-safety question at the same time.

The trade-off

Everything it gives you sits on the winter side of the ledger. It is not a heat-rejection product and will not rescue a hot west lounge in February. Being soft and pleated, it also has no business in a dusty scullery.

External venetian blinds

Hard west & north-west glazing

Aluminium slats again, but running in guide rails fixed outside the glass. We put these ahead of an interior blockout on a hard west wall for one reason, and it is a physical one rather than a stylistic one: heat turned away before it reaches the pane never enters the building at all, whereas heat absorbed by the glass sits there radiating at you through the evening. The bonus is that tilting them still leaves you the garden — you are not choosing between a cool room and a view.

The trade-off

It is the expensive end of this page, it changes how your facade reads, and it spends its life outdoors in a province where hail peaks in the first half of November between four and five in the afternoon.^[6] So: motorised, with a wind sensor, no exceptions. And since the estate committee will have a view on the colour, raise it with them early rather than late.

Roller shutters (shading)

West walls · exposed elevations

Rigid interlocking slats that roll down out of a headbox mounted outside the opening and cover it completely. Heat and glare are stopped before they reach the glass, and once the shutter is fully down the air trapped behind it gives you real insulation on a cold night as well. One point we would rather make plainly than have you assume: these are shading shutters. Security-rated shutters are a separate product line, built and certified to a different standard, and we quote them separately on request.

The trade-off

Of everything on this page, this changes the outside of your house the most. The headbox is real and has to be designed somewhere — flush into the lintel on a new build, surface-mounted on a finished one — which makes it an architectural decision rather than a measurement. And there is no dimmer: down means covered, not softened.

Folding-arm awnings

The entertainment patio

Rand for rand, this is the largest amount of usable house you can buy on this page. A Raslouw braai patio is not a decorative feature; it is where the family actually eats from October to April, and shade is the difference between a room and a hot slab. The neat part is that it reverses — fold the arms away in June and the low winter sun comes back onto the paving, which is exactly when you want it there.

The trade-off

It lives outdoors, unprotected, in a hail belt whose worst hour is between sixteen hundred and seventeen hundred.^[6] Our answer is a full cassette that swallows the fabric when it retracts, plus a wind sensor that pulls it in whether anybody is home or not. We treat both as part of the specification rather than as upsells.

Concealed / recessed blinds

New builds · double-volume windows

Every bracket, tube and motor disappears into a slot in the ceiling or the bulkhead; all you see is fabric arriving out of a shadow line. Raise the blind and the window is glass and frame again, which on a double-volume Raslouw living room is the whole point — nobody spent that money on glazing to hang hardware across it. Of everything here, this is the product most sensitive to timing.

The trade-off

The recess has to exist. Getting it drawn while the bulkhead is still open framing costs almost nothing; cutting one into a finished ceiling later is possible but seldom truly invisible. If you are already living in the house, a cassette pelmet powder-coated to your ceiling colour gets you most of the way there for a good deal less disruption.

Motorised blinds & automation

Wide stacking doors · anything exterior

On the four- and five-metre stacking doors these houses are full of, a motor is not an indulgence — it is what makes the blind get used. A sheet of fabric that wide is genuinely heavy on a chain, and anything that needs a pole fetched from a cupboard quietly stops being operated by about week three. There is a second, less glamorous argument: an exterior product without a wind sensor has no way of saving itself when a November storm builds at four in the afternoon.^[6] Automation is what puts that sensor in charge.

The trade-off

Power has to reach the head of the opening, one way or another — wired, solar or battery. Mid-build that is a length of cable pulled before the walls close and costs almost nothing. In a finished home a rechargeable lithium motor spares you the chasing and replastering, at the price of a charge a few times a year.

Three more sit on the window list at the foot of the page, because a new-build estate house throws up openings the ten above don't cover. Vertical & panel blinds stack neatly off to one side of a wide slider instead of hanging in front of it. Skylight & shaped blinds are made for the gable panes and stair-void glass that come with a double-volume plan. And zip screens pull down in side channels to shut a patio against wind, dust and the evening insects while leaving you able to see straight through it.

05 — The local constraint

The estate's own rules, and who has to say yes

There is a line running straight through the ten products above, and in Raslouw's secure estates and boomed complexes it is the line that matters. On one side: everything that lives inside an existing reveal. A roller, a venetian, a cellular blind — none of these alter one pixel of what the road or your neighbour's stand can see, so nobody has to approve them and nobody will ask. On the other side: anything that reads on the face of the building. Awnings, external venetians, roller shutters and the side channels for zip screens all change the elevation, and estates around here typically want that signed off, in a palette they have already agreed on.

None of which is an argument against the exterior products. It is an argument for raising them early. Take the estate on the doorstep: Blue Valley Golf & Country Estate carries a predominantly Tuscan architectural theme and runs a formal building-plan approval process,^[8][9] so an awning or an external venetian there gets chosen to sit inside that language rather than argue with it. Practically, that means three things from our side. Exterior hardware comes powder-coated, and the colour range is wide enough to match most facades properly. We talk the finish through with you before a single component is ordered. And if your HOA wants a specification on file, we write one and send it.

What we will not do is speak on your estate's behalf. We fit blinds; the guidelines are theirs. What we will do, at the measure, is say plainly which of the options in front of you touch the outside of the house — so the question reaches the right desk while it is still a question rather than a fitted product. One caveat in the interest of honesty: we could not find Raslouw's estate-by-estate architectural guidelines published anywhere online. Read the paragraph above as the general norm for estates in this part of Centurion and check your own HOA pack for the rule that actually binds you.

If the house is still going up, phone us now rather than at handover. Two things have a deadline. A concealed recess must be formed before the ceiling closes; after that it is a repair job. And motor cabling that costs almost nothing to pull through an open wall becomes chasing, patching and repainting in a finished one. There is a regulatory reason to talk to your architect too. SANS 10400-XA:2021 lifted the fenestration-calculation threshold from 15% to 20% of floor area, and it no longer distinguishes between the solar-heat-gain requirements of west-, north- and east-facing glass.^[10][11] On a house with the glazing areas these plans carry, it is worth asking exactly how your shading is being counted.

06 — The honest limit of a guide

What we'd still need to check on site

Everything on this page is what can be known about Raslouw from a desk. None of it is what can be known about your house. Five things settle the actual specification, and every one of them needs somebody standing in the room with a tape, a compass and a torch. It takes about an hour.

1 · What each wall actually faces

Estate roads curve, and houses follow them, so "roughly west" is not a specification when the sunsets themselves are spread across fifty-two degrees of horizon.^[4] Rotate a wall by twenty degrees and the honest recommendation can move from an interior sunscreen to something mounted outside the glass. We put a compass on every elevation before we write anything down.

2 · The reveal, and what is behind it

Depth decides whether the blind can sit inside the opening at all and how much light will creep around its edges. Square-ness is worth measuring rather than assuming; very few openings are perfect, and the fix is easier to design than to discover on fitting day. Then there is the substrate. Plastered brick, a drywall bulkhead and an aluminium glazing bar each want a different fixing, and the torch is for finding out which one you have.

3 · How exposed the patio really is

Awnings and zip screens live or die on this. Summer storms here build from mid-afternoon,^[7] and whether the house next door shelters your paving or channels the wind straight down it is obvious within two minutes of standing there — and completely invisible on a site plan.

4 · The route power has to take

Every motorised opening comes down to one question: how does electricity get from an existing point to the head of that window? Walking it usually turns up an answer nobody expected — a ceiling void, a cupboard back, a run behind a bulkhead. On a double-volume lounge or a five-metre slider, that walk is the difference between an install that looks designed and one that looks solved.

5 · What is on the other side of the pane

A neighbour's bathroom window forty metres away and one eight metres away are different fabric decisions. So is a boundary wall, an internal estate road, or a mature tree already doing half the shading for you — in which case the question we ask is whether it will still be carrying leaves in July.

07 — Two ways forward

Book the free expert measure

One consultant, at your house, with the fabric books and slat samples in hand. Every opening measured properly, every recommendation argued out loud, and a written quote broken down window by window so you can see what each one costs on its own. There is no charge and nothing to sign. If you would rather see a number before you see a person, the window list is folded into the same form below — fill in what you can and we'll send a range.

The measure costs nothing, and the quote comes back priced per opening

A person on site, hard hat and all if the house is still a building site

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Raslouw Blinds — window list

Take this round the house with a pencil, then copy it into the form at raslouwblinds.co.za afterwards. Width across first, then the drop, both in millimetres.

Rough sizes are enough — we'll come back with a budget range by the next working day. If measuring isn't your thing, leave the boxes empty and say so; the consultant measures free and you end up with exact per-window pricing whichever route you take. None of this is binding and none of it is required.

Room	Width (mm)	Drop (mm)	Inside or outside the reveal	Product	Remove

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Working out

Sources

Every figure on this page — geography, climate, regulation — comes from one of the eleven references below. Where we have reasoned outward from a source rather than quoted it, the text says so at the point it happens.

Everything Property — Suburb focus: Raslouw (western countryside edge of Centurion; a mix of surviving agricultural holdings, plots and small farms with new secure residential estates such as Raslouw Lifestyle, Raslouw Glen and Raslouw Manor; stands from ~200 m² to ~25,000 m²). everythingproperty.co.za — Raslouw
Seeff Property Group — Raslouw, Centurion area profile (a scenic suburb on the outer western reaches of Centurion; small farms, plots and modern residential security estates). seeff.com — Raslouw area profile
Wikipedia — Centurion, South Africa (coordinates approximately 25.859° S, 28.186° E; elevation ~1,453 m above sea level, on the Highveld). en.wikipedia.org/wiki/Centurion,_South_Africa
Conradie, D. (2018) "Sun, shade and natural daylight in South African town planning, with emphasis on Pretoria", Town and Regional Planning 73:47–67 — latitude 25.733°, noon solar elevation 87.7° on 21 December and 40.84° on 20 June, sunset azimuths of 243.35° and 295.76°, the finding that western-exposure afternoons run significantly hotter than mornings, and the guidance that horizontal overhangs suit altitude-dominated angles on northern facades while low azimuth-dominated sun wants vertical control. scielo.org.za — S2415-04952018000200005
Hong Kong Observatory — ultraviolet radiation at high altitude: "For every 1000 m increase in altitude, the UV radiation level will increase about 12%." hko.gov.hk — UV radiation at high altitude
Punge, H. J. et al. (2023) "Characteristics of hail hazard in South Africa based on satellite detection of convective storms", Natural Hazards and Earth System Sciences 23:1549–1576 — a convective season peaking in the first half of November over Gauteng, and a peak time of day between 16:00 and 17:00 South African standard time. nhess.copernicus.org/articles/23/1549/2023
South Africa-info — weather and climate: Highveld summers bring afternoon thunderstorms; winters are dry and mild with cold, frosty nights and virtually no rain from around April to September. southafrica-info.com — weather & climate
Seeff Property Group — Blue Valley Golf Estate, Centurion (a Gary Player signature 18-hole golf estate near Raslouw with a predominantly Tuscan architectural theme and 24-hour perimeter security). seeff.com — Blue Valley Golf Estate
Blue Valley Golf & Country Estate — Home Owners' Association (building-plan approval and construction process for the estate). bluevalleyestate.co.za
Roos Architects — summary of the revised SANS 10400-XA standard (2021 edition): the fenestration threshold rising from 15% to 20% of floor area, and no distinction now drawn between the solar-heat-gain requirements of glazing facing west, north or east. roosarchitects.co.za — revised SANS 10400-XA
SANS 10400-XA:2026 (Edition 3), The application of the National Building Regulations Part XA: Energy usage in buildings — the current compliance framework for building energy efficiency, which superseded the 2021 edition in March 2026. SABS — SANS 10400-XA:2026 (Edition 3)

Two things we would rather flag than let you find. First, the solar arithmetic in source 4 is computed for Pretoria at 25.733° south. Raslouw sits a shade under a tenth of a degree further south, so its true angles are fractionally different — we would rather publish the researched figures than a number we invented ourselves. Second, the hail, frost, rainfall and UV material describes Highveld conditions as a region, not measurements taken in this suburb; no station publishes a Raslouw-specific frost or hail record, and as noted above the estate architectural guidelines here are not online either. All of which points the same way: the useful reading happens at your house, not on a map.

Ready when you are

Enough theory. Let's go and stand in the room.

One visit, a compass and a tape, and a written figure against every opening in the house. Say no afterwards and nothing at all has been lost.

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