THE BUYING PROCESS

How is insulation calculated and who orders it for a build project? James Francis from ROCKWOOL® UK shares his advice

To meet Building Regulations and to ensure you order the right amount of insulation, it’s important to know who will order it, how it’s calculated and at what stage of the project it should be on site. Who calculates the amount of insulation you need?

The amount of insulation needed depends on the type of project it’s being used for, and calculating this amount is often a task for whoever is carrying out the work. If, for example, you were building a home, then you would typically employ the services of an architect or a specialist contractor who would calculate the quantity required.

In situations where a contractor isn’t being used, for example on a home renovation being carried out solely by the homeowner, there are resources available to help calculate the amount of insulation needed. Builders’ merchants can also be a knowledgeable resource to get valuable advice on materials needed.

When deciding and calculating insulation specification, solutions that deliver additional benefits beyond thermal performance should be considered.

How is it calculated?

A number of factors would need to be taken into consideration when calculating the amount of insulation required. Typically, the calculations depend on the desired U value target – the amount of insulation required to deliver the appropriate thermal performance – that would need to be met as per Part L of the Building Regulations [as per the table on page 134].

ROCKWOOL has a free online U value calculator tool that demonstrates the overall performance of a wall construction, floor or roof featuring ROCKWOOL insulation.

Who buys and orders the insulation?

If a project is using the services of a builder or contractor, then typically these companies would expect to order and purchase the insulation as part of all of the materials that are needed on site. For those who are building or renovating their home without the use of contractors, a variety of insulation options are available throughout the UK from builders’ merchants and retailers.

And at what stage of a project would insulation ideally need to be delivered?

The delivery of project materials depends on a variety of factors, such as space on site and which stage of the overall project the insulation will be installed. Most insulation is required at a fairly early stage of the construction process, so contractors and/or project managers should ensure that they leave adequate time for ordering and delivery so as not to hold up other works.

It’s also important to consider the storage of insulation, making sure that there is somewhere dry for it to be kept before it is installed.

This post and beam green oak frame certified Passivhaus has an enhanced version of Oakwrights’ Wrightwall and Wrightroof Natural system, which includes recycled cellulose insulation.

This self-build has wood fibre insulation between the studs, a high-density breathable chipboard layer fixed to the frame and a layer of Gutex Multitherm insulation added.

CAVITY WALLS ROCKWOOL stone wool insulation is suitable for cavity wall insulation (left). Some cavity boards can be fitted with a residual cavity just 10 mm wide, allowing slimmer wall constructions.