Home · External wall insulation (ETICS)
External wall insulationOnce it is done, external wall insulation looks like a brand-new facade. What you can no longer see is exactly where the quality sits: the spread of the adhesive, the reinforcement mesh, the detailing around every window. On this page we open up the full build-up — including the Belgian standards you can use to check the work. Ours included.
ETICS stands for External Thermal Insulation Composite System. The word composite matters most: it is not a stack of separate products but one composed system that is tested and approved as a whole.
The insulation goes on the outside, so the masonry now sits on the warm side. That removes the risk of internal condensation that internal insulation actually creates, and the mass of your wall keeps on buffering heat.
Concrete lintels, floor slabs, wall bases: with internal insulation they stay cold right through. A continuous outer skin takes them with it, and that is precisely where you feel the difference in comfort.
Nothing is opened up inside, no room has to be cleared, no floor area is given up. The works stay outside, on the scaffolding.
Buildwise explicitly recommends taking a complete system from a single manufacturer, preferably with a Belgian technical approval (ATG). Mixing components voids the fire classification, the stated insulation value and the system warranty.
You only do a facade once every thirty years. We build it as if someone were coming to inspect it afterwards.
— VediWorksEvery layer has one job, and every layer has measurable requirements. The figures below come from the Belgian ETICS Manual and from the Buildwise installation guidelines — so they are not house rules of ours.
Flatness, load-bearing capacity and moisture content are checked before anything is bonded. Loose plaster is chipped away, moss and dirt removed, old paint preferably taken off completely. A facade that has not yet reached its equilibrium moisture content has to wait.
Unevenness of up to ± 15 mm per 2 m can be taken up with adhesive mortarAt the bottom comes an aluminium starter profile that carries the first row of boards and seals it watertight. At every corner and every opening come profiles that are bedded into the mortar. The expansion joints of your shell construction are carried consistently through into the system.
3 fixings per running metre · joint of about 3 mm between profilesThe adhesive is applied as a perimeter bead plus dabs, so that the board bonds around its full edge and no air channel forms behind it. The boards go on in a staggered bond, tight against one another, with joints offset from the window corners.
At least 40% bonded surface for a rendered finishPlate anchors are added as soon as the substrate calls for them: in renovation over old paint or plaster, with mineral wool, on timber, and everywhere the wind load requires it. They are only fitted once the adhesive has cured, and are covered flush so that no point thermal bridges arise.
Typically 4 to 8 per m², the exact number follows from the ATG calculationThis is the layer that decides whether your facade is still crack-free in ten years' time. The alkali-resistant glass fibre fabric spreads the thermal stresses. It must sit fully within the mortar and towards the outer face — if it lies against the insulation, it does nothing. At every window and door corner comes an extra diagonal strip, because that is where the stress concentrates.
Mesh overlap ± 100 mm · diagonal strips ± 300 × 300 mm at 45°Window sills get a drip edge that projects far enough beyond the render and enough fall, so that rainwater runs away instead of running over your facade. Around every window comes a continuous sealing tape between the insulation and the joinery. This is the slowest part of the job and the part that determines the most.
Drip edge at least 30 mm beyond the render · fall of 5° to 8°A primer coat provides adhesion and an even suction, after which the final finish follows in the chosen texture and colour. Every facade plane is finished in one go, wet on wet, without restarts — otherwise you will see the join in it for years.
Colour with a lightness value above 20% (see the render page)Sources for the values quoted: the ETICS Manual (Xthermo, the Belgian sector federation) and the installation guidelines of Buildwise (formerly the WTCB). The exact number of anchors, the board thickness and the permitted colours are set out per system in the manufacturer's technical approval (ATG). We supply you with that reference along with the quote, so that you can check it yourself.
An ETICS facade rarely fails because of the insulation material. It fails on details that nobody can see any more once the scaffolding is down. That is why we set them out here — so that you know what to look at, whichever contractor you end up with.
One certified system from one supplier, with the ATG reference in your quote. A fixed crew that does the detailing itself instead of passing it on. And a photo record of every stage, including the layers you cannot see afterwards: the spread of the adhesive on the boards, the anchors, the embedded reinforcement mesh, the diagonal strips at the corners.
That photo record is not marketing. It is the only proof that can still be produced once the scaffolding is down.
Scaffolding, signage and sheeting off windows, doors and planting. Where the public domain is affected, we arrange the permit.
Cleaning, removing loose parts, repairs where needed, then the starter profile set level and the corner profiles.
Bonding the boards, fitting anchors where needed, and after the drying time the reinforcement layer with mesh and diagonal strips.
Base coat, decorative render wet on wet, detailing completed, scaffolding down, site clean, photo record handed over.
For an average family home it comes down to a few weeks from scaffolding to finish. That is not because of the number of working hours but because of the compulsory waiting times: at least 48 hours between the insulation and the reinforcement layer, and again at least 48 hours before the decorative render may go on top.
On top of that come weather days. We put a realistic period in the quote instead of a reassuring number, and let you know as soon as the weather shifts the schedule.
The works are entirely outside. You can carry on living there, carry on working and do not have to clear a single room. What you will notice: scaffolding around your house, windows sheeted off for a few days, and working noise during working hours.
What you do not have to arrange: scaffolding, signage, skips, the planning notification where one is required, and the clearing up afterwards.
External insulation brings your facade 11 to 21 cm further out — the insulation thickness plus about a centimetre of finish. That is not a detail, and it is the most honest conversation to have beforehand.
| What | What happens | How we solve it |
|---|---|---|
| Window sillsand thresholds | The existing sill no longer projects beyond the new facade and would let water run over the render | Extended or replaced with a sill that has enough projection and fall — included in the quote, not as extra work afterwards |
| Roof overhangand fascia boards | The overhang effectively becomes shorter; with a small overhang it can become too tight | We measure this up during the site visit. Sometimes a thinner board with a better lambda value is enough, sometimes the roof edge needs adapting |
| Building line and plot boundarysemi-detached and terraced homes | On the building line, on public land or on the plot boundary there is not always room to come further out | A notification or permit may be needed; with a party wall the neighbour's consent is required. We look into this beforehand and help with the steps |
| Roller shutter boxes, pipeworklighting, house number | Everything mounted on the facade has to come off and go back on — now onto a thicker facade | This is inventoried during the survey and appears as a line item in the quote, so that it does not become a discussion on site |
| The look of the facadebrickwork disappears | A rendered facade is a different home from a brick facade — for some that is the gain, for others the objection | If you want to keep the brick look, brick slips are the answer: insulating with a brick finish over the top |
The German Fraunhofer institute for building physics has been inspecting existing ETICS facades every five to ten years since 1975. That long-term research shows that a correctly installed system with maintenance lasts at least fifty years without serious defects; one facade examined still showed no technical damage after 29 years without any maintenance at all.
What comes up for replacement sooner is the final finish — and you can clean or repaint that without touching the system.
You can read more about cleaning, algae, cracks and repainting on the page about render and decorative plaster.
Photos of your facade, a few clicks, and you see an indicative price range straight away. After that comes a free on-site visit in which we properly measure the substrate, the sills and the overhangs.
VediWorks is one of Vedi Group's four companies. Interior painting, a post-construction clean or maintaining shared areas: one contact, the same crews, the same standard.
