top of page


EWI stand for External Wall Insulation. There are many systems from rail systems to Warmshell systems, but the most common one used on domestic properties is a EPS stuck to the exterior of a property by adhesive and fixings to create a warm shell around your home. 

There are also a lot of different types of insulation boards on the market like wood fibre, mineral fibre and EPS (expanded polystyrene). EPS is the most commonly used for most cases, but will depend on a case by case study.

Once the insulation is fitted a thin coat render system is then applied on top. The renders used here, has a very high level of binders and polymers in to help stick to, and move with the insulation. These renders also have breathable qualities, helping moisture to escape the property and stopping the build up of mould.  The whole structure will have a nylon reinforcing mesh embedded in the basecoat for strength and rigidity. Like with all thin coat renders it is finished to a flat, smooth finish ready for a topcoat to be applied on the top.

Once the basecoat is complete. its just a case of choosing a topcoat. We would recommend a silicone or acrylic topcoat as these are the most superior and long lasting on the market.

If a full guarantee is needed, we would need to seek a manufacturers rep to give us a specific specification about the project, and have a rep sign it off. There are lots of options and guarantees on the market, please get in contact and we will be more than happy to help.

The EWI Process

EWI Breakdown.png

Case Study- Cottage In The Cotswolds

Here we have taken all light fitting, downpipes and wall ornaments down ready for the insulation to be fitted. A metal base rail is fitted to the damp course level as a starter for the insulation.


Phase 1

Phase 1- Scaffold and Prep Building Ready for EPS

Here a 90mm graphite EPS has been fitted to the house. It has been stuck with an adhesive and mechanically fixed.

Phase 2

Phase 2- Fit EPS Insulation

Once the EPS was fitted we then applied a thin coat render system over the insulation, in two coat totalling 6mm thick overall and embedding reinforcing mesh inside. It is then floated to a smooth, flat finish ready for the topcoat.


Phase 3

Phase 3 - Thin coat Render 

We then primed the whole building and sprayed a 1.5mm Silicone Topcoat on. After striping the tapes off and cleaning up, the scaffold was dropped, completing this old cottage in the Cotswolds. 


Phase 4

Phase 4- Apply The Silicone Topcoat

This part of the  cottage in the Cotswolds was over 100 years old and had a solid 9 inch walls. We used a 90mm graphite EPS to bring this property's  U Value down to 0.3 and increase its thermal efficiency. The customers had new windows and door fitted before we arrived helping to achieve the U Value. The windows were manufactured with extended sills to allow for the fitting of the EPS and render, stopping the need for a under-sill to ne fitted. 

Over the EPS a K Rend specified, thin coat render system was applied with a cream TC15 Topcoat as the finish. 

If you have a question or something hasn't been covered in this section please contact  us.

bottom of page