The boards are made from either plywood, sheet metal, cement, oriented strand board (OSB) or magnesium oxide board (MgO). The rigid insulation core is usually made from expanded polystyrene foam (EPS), polyurethane foam, extruded polystyrene foam (XPS), composite honeycomb (HSC) or polyisocyanurate foam.
SIPs are an excellent choice for self-build projects, resulting in a building which is strong, well-insulated and generally cheaper and greener to run, as well as being simple to install and saving you time and money on your project.
How Does it Work?
Put simply, SIPs are a layer of foam insulation between two boards of panelling made up of various materials. They are used for many different things within a building project, including external walls, roofs, floors and foundation systems, and they are generally no more expensive to use than a timber frame once savings in labour time, reduced waste and savings on heating further down the line are taken into account.
The Advantages
There are plenty of pros to using SIPs in your self-build project:
- Short construction times – Because the manufacturing of SIPs is standardised and they arrive as an ‘all-in-one’ product, they take far less time than a framed home to fit together and that reduces labour costs.
- Better overall cost savings – While they may seem expensive compared to some building materials, SIPs can save you money in the long-run. Their superior insulation properties mean they are more energy efficient, and they take far less time to bring in from off-site and put together than a timber or steel frame would.
- Better environmental performance – Especially when you are trying to get planning permission approved, being able to point to your green credentials through the use of SIPs can be beneficial to getting your self-build project off the ground. Better insulation means your home will be more efficient, while SIPs also offer greater resistance to damp and cold than many other building materials. Unlike timber they will not suffer from shrinkage when exposed to damp, making them more long-lasting.
- Reduced mortgages from some lenders – Some mortgage lenders are now offering reduced rates for those building their own homes with SIPs.
The Disadvantages
- No on-site changes – SIPs have to fit perfectly on the dimensions of the foundations, which means you can’t make any last minute changes. You will have to make all the decisions and sign off the plans beforehand, so there is less flexibility if you have a change of heart.
- Exposure to damp – SIPs can be easily damaged by damp and need to be protected.
- Finding skilled tradesmen – Many tradesmen aren’t used to working with SIPs, so it can be harder to find someone qualified to install your panels.
- Need for a ventilation system – SIPs make for very air-tight homes, but that means you’ll need to install a mechanical ventilation system, which can be costly.