FAQ – About your property

1. Can external wall insulation be installed on any property?

EWI suits a wide range of properties, both existing and new-build. If fitting to an existing property, you’ll achieve the best results on a solid-walled (i.e. non-cavity) property, although considerable improvements in heat retention can also be achieved on properties with cavities. As the insulations boards need to sit on a flat surface, the best surfaces are rendered walls, concrete panel/cast-concrete, brickwork or blockwork. We also have systems for new-builds and extensions. Stone-built walls with exposed stone surfaces are not generally suitable because of the uneven nature of the surface. For a free consultation to explore whether your property is suitable for EWI, call Greenhus on 01822 819 911, or use our contact form.

2. Do I need planning permission for external wall insulation?

EWI does not usually require planning permission, and can be installed under a Building Notice. (Greenhus applies for this on your behalf and manages the process through to the issue of a Completion Certificate.) You will, however, require planning permission if you live in a National Park or an Area of Outstanding Natural Beauty (AONB). It may also be required if you propose to substantially alter the appearance of your property, e.g. if you change from brick to render, although this is rare. Greenhus will supply product specifications, photographs and other supporting documentation to help you with your application, and has never experienced a rejection of an application. Speak to us on 01822 819 911.

3. Can external wall insulation be installed on an old property?

Generally, yes, although older properties (“traditionally-built”) require special considerations that are established at survey stage, with particular reference to the need (or otherwise) for the property to breathe. This will dictate the type of system we will offer. To establish whether your home is suitable for EWI, call Greenhus on 01822 819 911, or use our contact form.

4. Can external wall insulation be installed on a stone-built property?

Generally yes, although the insulations boards need to sit on a flat surface, so the walls would need to be rendered. Stone-built walls with exposed stone surfaces are not generally suitable because of the uneven nature of the surface, although they could be rendered as preparation to accept EWI. For a free consultation to explore whether your property is suitable for EWI, call Greenhus on 01822 819 911, or use our contact form.

5. Can external wall insulation be installed on a lime-rendered property?

Yes. Lime-render allows a building to breather, so it is important that the application of EWI doesn’t compromise this. We would therefore specify a system using wood-fibre insulation rather than the much more common EPS.

6. How is external wall insulation installed on a property with no roof overhang or soffits?

Where a property has no roof overhang or soffits, the usual option is to use a verge trim to seal the top of the insulation – click here for a picture. An alternative would be to extend the roofline, although this option is invariably dismissed on cost grounds.

7. What happens with all the pipes on my wall, like soil pipes/waste pipes/overflows if I have external wall insulation?

Your external wall insulation will add thickness to your walls, so any pipes currently passing through your walls (e.g. waste pipes and overflow pipes) will be extended so that they function as they do presently. Wall-mounted downpipes will be adjusted and re-fixed (or replaced). Soil pipes often cannot be reinstated (they may be cast iron, or plastic that has become brittle) so these are replaced. Amending pipework is frequently the first task our installers perform; pipes are extended and temporarily fixed. This means your home or business continues to function as normal, and our installers can work “behind” the pipework to apply your system. When the system installation is complete, pipework is attached securely and permanently to your new wall.

8. What happens to external fittings if I have external wall insulation?

We take note of any existing external fittings and discuss and agree any that will be replaced. Depending on the weight carried by the fitting (e.g. hosepipe reels and hanging baskets are considered as “heavy” whereas a house name-plate is considered “light”), we will apply appropriate fixing points in the system.

9. What happens to my window reveals and window sills if I have external wall insulation?

The addition of EWI will increase the depth of your external reveals, and in the majority of installations will mean your existing window sills are lost. We will fit new sills or extensions to existing sills and have a variety of options that can be viewed here. If you are replacing your windows as part of a refurbishment or upgrade, it may be worth re-positioning them to the outside of the existing wall. When we add your EWI, your external reveal is only then as deep as the “thickness” of the EWI. (If considering this, please consult with your window installer to ensure there are no technical implications re: lintels/arches.)

10. What are the advantages of external wall insulation v. internal wall insulation?

By using EWI, the dew-point (i.e. the point at which condensation occurs) is moved outside the fabric of the building, providing long-term protection of your building materials. This is not the case with internal wall insulation (IWI). Installing EWI is a process that allows you to use your home as normal, whereas installing IWI is an intrusive process that will compromise the way you use your rooms. Plus, your rooms will become smaller. IWI can, however, be effected on a room-by-room basis, whereas the economics of EWI dictate that the whole installation be performed at one time, so IWI could be a more cashflow-friendly solution. IWI is cheaper than EWI, but doesn’t offer any protection to the outside of your building or improvements in appearance.

11. Can new windows be fitted with external wall insulation?

Yes, although replace them before we do your installation. We are then able to finish against existing fittings and features, which will give far better appearance and performance than if other trades need to cut into your EWI and then attempt to make good. It may be worth re-positioning your new windows to the outside of the existing wall. When we add your EWI, your external reveal is only then as deep as the “thickness” of the EWI. (If considering this, please consult with your window installer to ensure there are no technical implications re: lintels/arches.)

Discover how External Wall Insulation from Greenhus can transform your home or business premises - complete our Contact Form and we’ll call you back, or speak to us on 01822 819 911

To find out how Greenhus can help you plan a great improvement to your home or business,
complete our Contact Form or call us on 01822 819 911
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