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To Spray or not to Spray? A brief guide to spray foam insulation

What is Spray Foam Insulation?

Spray foam insulation in residential property generally refers sprayed polyurethane (PU) foams. These are often applied to the underside of roof coverings in domestic dwellings.

Spray foam insulation in a roof space

What are the reasons for applying spray foam?

There are two main types of spray foam insulation used in domestic dwellings:

1. Closed Cell Polyurethane Sprayed Foam

2. Open Cell Polyurethane Sprayed Foam


Closed Cell:

This is primarily used to stabilised failing roof coverings. It does have a minimal value for improving the thermal performance of buildings, but this is not generally its primary function.


Open Cell:

This is generally used to improve the thermal performance of buildings.

What are the potential issues?

There are a number of potential issues where spray foam insulation has been applied to the underside of roof coverings including:

·      Saleability / mortgage-ability issues

·      Restricted access / visibility to assess condition of concealed areas

·      Restricted access / ability to carry out maintenance and repairs

·      Can make roof coverings un-recyclable and un-reusable

·      Creates a waste disposal issue at the point when roof renewal will inevitably be required

·      Can restrict ventilation in roof space, causing dampness and condensation issues if incorrectly installed

·      Some types may be combustible and/or release noxious fumes

Home-owner worrying about spray foam insulation

Our advice

The potential issues described are not necessarily apparent in all cases where spray foam insulation has been applied. However, whilst it is possible for spray foam insulation to be correctly installed, in our experience many spray foam installations:

·      Have been installed for the wrong purpose

·      Have not been fitted to the requisite standards

·      Have not had sufficient evaluation and design work carried out prior to installation


In many cases, this results in homeowners having to expend considerable sums for complete removal of roof coverings and associated structures.

Please contact us if you have any queries regarding the installation of spray foam insulation, whether you have already had it applied previously or are simply looking for further information about a potential future installation.


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