Frequently Asked Questions

Where can I use Celotex insulation?

Celotex insulation is multi-purpose and can be used in a variety of applications including pitched and flat roofs, floors and walls within both new build and retrofit projects.

The insulation listed on this website has been specifically selected as the main options for 'top-up' insulation where existing levels of insulation are present and will be increased to improve the energy efficiency of your home.

For full details of all Celotex products and their specific application, please visit www.celotex.co.uk

What thickness do I need to use?

This will depend on the type of installation you are carrying out. It may also be that you are attempting to meet certain building standards with your insulation in which case the thickness needs to be pre-determined prior to purchase.

Factors such as joist depth and existing levels of insulation should also be considered. It is important that the type of installation and scope of your project is known before you purchase your insulation thickness.

Currently there is no binding regulation requirement for 'top-up' insulation.

I want to just insulate my roof between rafters rather than at joist level. Can I do this?

Yes you can though insulating at rafter level is more complicated and technical than at ceiling joist level.

This is because the method of installing will depend upon many factors including the roof design, rafter depth and whether the roof space is a ventilated or unventilated system. Depending on which construction detail you have will determine whether an allowance has to be made for ventilation.

In many circumstances, installing insulation as a top up solution between rafters also means that the existing insulation between the joists may need to be removed to prevent a risk of condensation.

Celotex recommends as a top solution that insulation is installed at ceiling joist level as the most effective method.

Can I use Celotex products in a loft conversion?

Celotex products are very popular in loft/attic conversions though often have stricter conditions of thermal performance and are more technical in terms of design and construction than top up procedures. Please visit Applications for further guidance on both loft and garage conversions.

What protection should I take when installing Celotex?

Whilst using Celotex is not hazardous, simple protective measures should be taken. This includes wearing gloves as aluminum facers can be sharp. Dust masks and eye protection should also be used to prevent inhalation of dust or contact with eyes. When installing boards, a crawling board across the joists is recommended to provide maximum protection in the loft space.

I have some boards left over. What can I do with them?

Before disposal of the product, ensure that all areas of your installation have been covered so to prevent any heat loss through small gaps that may have been missed especially at eaves. Celotex product is landfill safe and can be disposed of through standard waste recycling channels.

I have researched other insulation material and they seem cheaper. Why should I use Celotex?

There are many reasons but most importantly Celotex offers one of the best thermal performances of any insulation materials. This means the same energy savings can be made but with far thinner solutions allowing you to save space.