WHAT IS A SIP?

The biggest advantage in using SIPs is mainly an installers advantage due to the time saved on-site. Think about it - if the company can install in 3 days instead of say 7, that’s a massive increase in productivity and thereby, profit. The team using SIPs has started a second installation before the company using Traditional methods has finished their first..! Conclusion: Big advantages to installers, but little advantage to the customer, other than the installers have come and gone a few days earlier.

There are a number of SIPS panel suppliers around the UK, however most of these are large suppliers feeding the big builders. They are certainly cheaper to produce than a Traditional method so manufacturers of garden rooms and offices love them as they are able to offer competitive pricing or make bigger profit margins. Conclusion: Big profit advantage to the installer or possibly cheaper prices for the customer.

SIPs panels are large, typically at least 8’ x 4’ so access to site needs to be sufficient to get these components to the build location. Getting into tight spaces is sometimes impossible with these large panels. Conclusion: Some customers may not have sufficient site access for a SIPs built structure.

Another advantage in using SIPs is that you do not need a highly skilled workforce to erect them. Very often a company will use low-skilled foreign sub-contractors for the installation. This saves the installer more money as this type of labour is much cheaper than time-served UK carpenters. Conclusion: Again the installers big advantage is in being able to use cheaper, unskilled workers to erect them rather than time-served tradesmen, making a bigger profit in the process.

SIPs can work well when a building is designed to standard panel sizes so that orders placed with the manufacturing factory can be mass produced. This maximises factory efficiency but limits the overall design flexibility. Big factories don’t like small quantities of bespoke sizes. Prices and lead times increase. Conclusion: Standardised sizes will be pushed during the sale process and the customer persuaded that bespoke sizes will be much more expensive.

SIPs panels should not be allowed to get wet during construction because if water gets into the panels the moisture has no way to escape from the composite structure. This can build-in the problem of mould. Mould in any timber structure is a massive problem, but in a SIPS building it is unfix-able. Mould is also a serious health issue, and can significantly impact the well being of occupants. By contrast, in a Traditional timber framed wall, the structure is allowed to breathe, so the timbers can dry out even if moisture does get in during installation. Conclusion: SIPs built structures should not be erected during inclement weather, or they should be weather protected, due to the high risk of rainwater saturation becoming ‘locked-in’, resulting in mould propagation and subsequent structural rot.

This is the biggest issue with building a garden room or office using SIP panels - it's so airtight that it becomes a sealed coffin. Yes, its got slightly better U-values (not that you'd notice the difference). But it can’t breathe, and neither can you. Yes, the large Housebuilders have in recent years started using SIPs, but they are subject to Building Regulations and must make their structures breathable using complex mechanical air flow & air replenishment systems. This is unrealistic in a garden room, these devices are too big, too complex and too costly to install. So moist air will just linger, and migrate into your plasterboard, creating long term mould issues. Some companies say they solve this problem by fitting an extractor fan in the wall and by providing an opening window. The only way this works is by leaving the window open, even in freezing winter..! Conclusion: Unless effective mechanical ventilation systems are installed (almost impossible in a garden room), in our opinion SIPs panels are not suitable for building garden rooms