How to save time when installing a flat roof

4 June 2021 Kingspan Insulation UK

Here in the UK, making the most of good weather is essential on any site and is particularly important when fitting a flat roof. If roofs can be made weathertight sooner, it not only means internal trades can get to work earlier but may also allow roofers to take on additional contracts. 

One way to save time when fitting a warm deck flat roof construction is by looking at fall provision. Traditional methods such as laying screed to a fall or fitting timber firrings (angled battens) beneath a plywood deck can take up a lot of time. Tapered roof insulation systems, such as Kingspan Thermataper, can offer a simpler alternative. In addition to standard flat insulation boards, they also feature tapered roofing boards and hip and valley boards, allowing them to provide drainage and insulation in a single system.

How tapered roofing compares with screed laid to fall approaches

As anyone who has hauled bags of sand or concrete up to a roof will know, laying screed on a roof can be a fairly major undertaking, particularly if mechanical lifting is unavailable. Tapered roof insulation systems offer a lightweight alternative which is much easier to transport around site.

Learn more about how tapered roof insulation can reduce the weight of a roof.

Once up on the roof, the screed has to be carefully laid to the correct fall and then left to dry. With a standard cement: sand screed mix this can take around one month for every 25 mm thickness. On large roofs this can easily take 200 days or more and only then can the insulation be fitted and the roof finished. In contrast, tapered roof insulation systems can be fitted with a dry installation using mechanical fixings. This means that even on large and complex flat roofs, the above deck construction can be completed in a matter of days rather than months.

Quick-drying screed options are available which can cut drying time down to around 7 days per 25 mm thickness. However, these products are also 40-50% more expensive than a standard screed mix. With research showing tapered roofing systems can already deliver considerable savings over the standard cement: sand screed, it is likely that quick drying screeds will add extra cost to a project and may still take several weeks to dry.

Learn more about how tapered roof insulation systems can help to reduce project costs.

How tapered roofing compares with timber firrings

Timber firrings provide a much lighter alternative to screed approaches and, as with tapered roof insulation, they also require no drying time. However, these materials are typically supplied as individual components. This means it is up to the roofer to ensure they are cut and laid out to provide the correct fall. This can be a time-consuming task, particularly on larger, more complex roofs. They also require the insulation layer to be fitted separately and U-value calculations to be carried out to ensure you have the right thickness of material.

In contrast, we offer a dedicated tapered design service to support all Kingspan Thermataper installations. Once supplied with the roof plan, our team generate a system layout to ensure the tapered roof insulation meets your drainage and thermal performance requirements. 

Learn more about our tapered design service.

Once delivered to site, they can be simply fitted together following the plans supplied, allowing a fast and accurate installation and ensuring the completed roof provides the drainage and insulation expected.

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