SIPS -Structural Insulated Panels are the building system of choice for many garden room designers. This is because they create an insulated envelope and are quick to install. The thing is, SIPS garden rooms are not all built equal.
Garden room designers such as Garden Spaces, Green Studios and Swift use the same SIPS panels that are used in housebuilding. The SIPS panels create the highly insulated core at the heart of their multi-layer build-ups.
The combination of the SIP and the multiple additional layers on the external and internal sides, offers a high spec finish, the same as you would find in a modern timber-framed house.
Layers you will find in a quality SIPS garden room build-up:
- External cladding
- Treated batten to create an air void behind the cladding
- Breather membrane
- SIPS - Structural Insulated Panel
- Treated batten to create a service void for the electrics
- Interior wall lining
This multi-layer build-up while producing the best quality garden rooms, that will add value to your home, is expensive material-wise, and installing the multiple layers takes time.
Over the years, we have read a lot of garden room specifications. We often simply see Structural Insulated Panels listed in the specification. There is no mention of the thickness. Because of this, it can be difficult to compare your options without asking the company for greater detail.
Different thicknesses of SIP are used
We know that many buyers have thought they were comparing like with like because Structural Insulated Panels were listed in all the specs they were looking at. The reality is that they probably weren't.
You will find that some companies use 75mm thick SIPS while others will use 150mm thick panels. Some companies will go even thicker to 200mm. The thicker the insulation, the lower the U-value, the better insulated the room will be and the less it will cost to heat and cool.
While we are talking about the thickness, be aware that when referencing the thickness of the panel, the measurement relates to insulation in between the sheet material. The sheet material either side is added onto this measurement.
All in one SIP
Some garden room companies have taken the SIP concept and redesigned it to reduce the number of layers in the build-up, which means their buildings quicker to install and more cost-effective material wise.
They replace the OSB board that is commonly used, on one or both of the faces. They will most commonly replace the internal leaf with a decorative surface that can form the room's interior.
Layers you will find in a custom SIPS garden room build-up:
- External cladding
- Treated batten to create an air void behind the cladding*
- Breather membrane
- SIPS - Structural Insulated Panel
- Interior wall lining
*Some companies omit this treated batten and air space layer, they fix the cladding straight over the breather membrane. Doing this speeds up the build even further.
If you are looking at a garden room with this build-up, you will want to check how the electrics are fitted. Because the internal face of the SIP is forming the interior finish, you don't have a service void. Because you want to avoid cutting into the insulation, you may find that the electrics are surface mounted. Practically there is nothing wrong with this, but it is not as streamlined aesthetically as flush sockets are.
Be mindful when comparing your options
There is no right option when choosing a SIPS garden room. However, you need to be aware that not all SIPS specifications are equal, and you need to know which system you are buying.
