When solid wall insulation is installed on brick or block work, it is very important the insulation material used stays in place. This goes with out saying to be honest: the reason being if the insulation were to move once installed, the whole of the system would come away from the wall – not ideal!
There are three different ways to attach the insulation boards to the wall:
- Attach with an adhesive (wet system)
- Attach with mechanical fixings (dry system)
- A combination of 1 & 2 (the best system!)
At EWI Store, we offer the BBA-approved EWI Pro external wall insulation system. This system is great for improving the thermal comfort of your home, lowering energy bills and also giving your property a complete facelift. It is also a belt-and-braces system: that is, it uses a combination of both adhesive and mechanical fixings.
You might ask why we bother – there is certainly more work if you are sticking the boards to the wall first with adhesive and then using supplementary mechanical fixings.
There are several reasons why we recommend a wet fix system with supplementary mechanical fixings
1. We want to sell solid wall insulation that lasts!
If you use only adhesive or mechanical fixings then the insulation boards are never held in place as firmly as when you use a combination of the two. We want to sell systems that are going to last many decades once installed, so we always advise to use both adhesive and mechanical fixings.
2. Dry fix only systems can suffer from draughts!
If you use dry fix systems then cold draughts can travel up the back of the boards, limiting the impact of the insulation. The cold draughts can accelerate the rate of heat loss, but if the winds are strong enough they can also try and pull the insulation from the wall.
Using the envelope method to apply the adhesive on each board means no draughts can travel behind the boards. This limits heat loss and ensures that the boards are held firmly in place.
3. Adhesive acts as a leveller!
The great thing about the UK is that we have some of the most diverse building stock in the whole world. Historically, we have made houses that are going to last – which is great – but it is fair to say that building methods from yesteryear didn’t always result in a straight wall!
By using adhesive on the back of the insulation boards, you can help level out some of the discrepancies in the wall. Obviously it is not going to be possible every time if the wall is really wonky, but it should certainly help take out some of the kinks!
We often refer to the EWI Pro external wall insulation as a belt-and-braces system: i.e. you are going above and beyond what is potentially required. But if you want these systems to last then we certainly recommend it is worth doing!