External Wall Insulation & Rendering
Roughly a fifth of Scotland's housing stock is solid wall — no cavity, no insulation, and up to a third of the heat going straight out through it. This is the upgrade that makes every other upgrade cheaper to run.
Why It Matters
You Can't Generate Your Way Out of a Leaky House
Solar and heat pumps change where your energy comes from. Insulation changes how much you need in the first place — and that saving never degrades, never needs servicing and never goes offline.
~35%
of heat lost through uninsulated solid walls — the single biggest leak in most older Scottish homes
2–3 bands
typical EPC improvement, which matters at sale and is already a hard requirement for many landlords
30+ yrs
expected life of a properly installed EWI system with silicone render — fit it once
What We Offer
Rendering & EWI Services
External Wall Insulation
We fix 60–100mm of insulation board to the outside of your walls, then finish it with a mesh-reinforced basecoat and render. Because the insulation sits outside the masonry, you lose no internal floor space and the walls stay warm — which is what stops condensation forming.
Silicone & Monocouche Rendering
Applied over EWI or directly onto sound existing walls. Silicone render is breathable, flexible and self-cleaning, which matters in a wet climate — it doesn't trap moisture or crack the way older sand-and-cement finishes do. Wide range of textures and colours.
Heat Pump Preparation
A well-insulated home is what lets a heat pump run at low flow temperatures, which is where it's genuinely 350–400% efficient. Insulating first usually means we can specify a smaller unit — often £2,000–3,000 less — that costs less to run every winter after that.
Repairs & Recovery
Failed pebbledash, cracked cement render, damp patches and blown areas. We strip back to sound substrate and rebuild the system properly rather than skimming over a problem that will come back in two winters.
The Build-Up
What Actually Goes on Your Wall
EWI is a system, not a product. Every layer does a job, and skipping one is where failures come from.
1
Substrate preparation
Existing render assessed and made good, rainwater goods removed, sills and reveals prepared. Anything unsound comes off before we start.
2
Insulation board
60–100mm EPS or mineral wool, mechanically fixed and adhesive-bonded. Thickness is set by your wall construction and the U-value we're targeting, not by a standard spec.
3
Reinforced basecoat
Polymer basecoat with an embedded fibreglass mesh. This is the layer that stops cracking, and it's the one most often skimped on.
4
Primer & finish render
Silicone or monocouche topcoat in your chosen colour and texture, plus new beads, sills and reveals so the detailing looks deliberate rather than patched.
🔢 Where this sits in the order of work
If you're planning more than one upgrade, insulation comes first in almost every case. It permanently reduces how much energy your home needs, which means a smaller and cheaper heat pump, and it makes the solar sizing decision easier because your demand is stable and predictable. We survey the whole property and give you the sequence that costs you least over ten years — including when that means doing less work with us this year.
How It Works
Survey to Finished Wall
A typical semi-detached EWI job runs 2–3 weeks on site, weather depending.
1
Survey & Assessment
We check wall construction, existing render condition, damp, and whether planning or building warrant applies to your property.
2
Design & Fixed Quote
Insulation thickness, finish, colour and detailing agreed, with a fixed price and cash and finance figures side by side.
3
Installation
Scaffold up, system applied layer by layer with proper curing time between coats. We don't rush render in bad weather.
4
Sign-Off
Rainwater goods refitted, site cleared, and a full handover pack with the system specification and warranty details.
Common Questions
EWI & Rendering FAQs
How do I know if my walls are solid or cavity?
Most Scottish properties built before roughly 1930 are solid wall, and many stone-built properties well after that. A quick check is the brick pattern: if you can see short ends appearing regularly in the coursing, it's likely solid. Wall thickness at a window reveal is another indicator. We confirm it properly at survey — and if you already have cavity walls, we'll tell you that cavity fill is a far cheaper route than EWI.
Will it cause damp problems?
Done properly, the opposite. EWI keeps the masonry above dew point, which is what stops interior surface condensation and the mould that follows it. Problems arise when a non-breathable system is put on a solid stone wall that needs to breathe, or when detailing at sills and reveals is done badly. We specify breathable build-ups on traditional construction and we detail the junctions properly — that's most of the job.
Do I need planning permission?
Often not, as EWI on an unlisted house frequently falls under permitted development. It does change the external appearance and wall thickness though, so listed buildings, conservation areas and some flatted properties need consent. A building warrant may also apply. We check your property's status at survey stage and tell you what's needed before you commit.
How much does it cost?
It depends heavily on wall area, access, existing render condition and the finish you choose, so an honest number needs a survey rather than a web page. Pay outright or spread it on finance with no deposit — we show both figures on the quote. Whatever the number, it's worth weighing against the fact that the saving continues for thirty-plus years with no maintenance and no equipment to replace.
Can you match my neighbours' finish?
Usually yes. Silicone renders come in a wide range of colours and textures, and we can match most existing finishes closely enough that a semi-detached pair still reads as one building. In conservation areas the finish may be specified for you as part of the consent.
Find Out What Your Walls Are Costing You
Book a free survey. We'll assess your wall construction, tell you what a proper EWI system would involve, and give you a fixed price — with no obligation and no hard sell.
Or call 07810 109060 — Mon–Fri 8am–6pm