Best cost effective insulation in walls 100 mm

Best Answer

"100mm isotherm or similar mineral wool insulation is the most cost-effective to achieve correct u-values etc, hope this helps"

"The best way for a 100mm cavity is to use the new 50mm eco therma board or the Celotex board and it still lets the cavity to breathe but also the board keeps the heat in and also less chance of the cavity being breached in the future but the cheaper version is to the cavity earth wool dry therm slabs."

"It’s ok to do this using concrete block on both skins but internally you would be better off using thermalise blocks as they are heat efficient and have more thermal value than concrete block"

"this can affect the movement's of your property at all aspects of the choice of your extension improvement's, the values and condensation of the weather throughout its existance."

"Build with block, dot and Dab the plaster boards, then rather than plaster,
Externally
Make sure 100mm cavity then brick up.."

"Single-storey extensions are simpler to build and less substantial than two-storey; so cheaper. Choose standard-sized windows and doors which are easier to install and more affordable. If possible, avoid building near drains or other buried services as complicated groundworks will increase costs.

Before you start planning your extension, work out whether the cost of building it and fitting it out is equal to – or hopefully less than – the amount it might add to your home’s asking price. You can do this by talking to an experienced local estate agent.

As a general rule, the more square footage you add, the more your home’s value should increase (but beware of ceiling prices in your area – it could mean that an extension does not make economical sense). However, the bigger the extension, the more it will cost.

By contrast, smaller extensions, with less square footage might give you extra space, but don’t tend to be very cost-effective."