Helpful Info
Cost Saving Benefits
With standard masonry construction, cold air from the external cavity has a free passage into the building through penetrations made by the first-floor structure e.g. hollow-core concrete slabs, timber joists, webbed eco joists etc. In most cases this floor to wall junction is either poorly sealed or ignored entirely. This dramatically increases wasteful heat transfer across the entire structural element, impacting negatively on building space heating costs and comfort of its occupants.
Leakage through the hollows-core slabs.
Leakage around the joist ends.
Leakage around really off standard joists.
Typical Example
Building Type: Two Storey Detached Type Dwelling
External Walls: Twin-leaf masonry with 150mm full fill cavity wall insulation
First Floor Structure: 150mm precast hollow-core concrete floor slab
Internal Floor Area: Approximately 150m²
The precast hollow-core slabs will rest on the internal leaf of blockwork, with the open ends exposed to the cavity wall. Cold air will flow freely through the hollow-cores and into the house via joints & service openings in the slab. Heat rising from the ground floor rooms will dissipate once it reaches the cold slab.
Often people will try to overcome this problem by fixing insulation boards to the first floor slab. This can be an expensive and time consuming task and is by no means a practical solution. After all you wouldn’t insulate an internal wall, so why insulate an internal floor? Instead of trying to limit the effects of this cold air infiltration, it would much easier and cheaper to prevent this air leakage from occurring in the first place. This is where Aerstad fits in.
Insulating the first floor of this particular dwelling would cost approximately £1300.00 i.e. 52 no. foil faced insulation boards (thickness 50mm) at £25.00 each *subject to change*.
Aerstad System will stop cold air infiltration, improve the thermal properties of the concrete floor slab, and reduce the initial expenditure by almost 50%. By installing Aerstad this initial expenditure is removed.
When combined with the improved U value performance of your external walls and the significant improvement in air tightness it’s easy to see why Aerstad is an essential component in any new building.
