ᐅ Compensating for insufficient parapet height using rigid foam insulation boards

Created on: 10 Jul 2017 08:53
J
joegamble
A friendly "hello!" to everyone!

We are currently in the shell construction phase. The building is using a Wienerberger Plan T-10 block. The window openings are mostly finished. According to the plans, the sill height should be 104.5 cm (41 inches) above the top of the foundation slab. The masonry has been built up to about 101 cm (40 inches), which corresponds to four courses of the Plan T-10 block. So, about 3 cm (1 inch) are still missing to reach the desired sill height. Our site manager suggested compensating for the missing height with a 20 mm (0.8 inch) Styrodur board.

My question is whether this is technically sound and if the Styrodur board might compress once the windowsill is installed and subjected to load (for example, if someone leans on it). If the board compresses, I am concerned that the windowsill could crack or break.

Am I just overthinking this, or is my concern justified?

Good luck
J
joegamble
10 Jul 2017 21:56
No, no kitchen units under a window. We considered what height we preferred for the windowsill and settled on 87.5cm (34.5 inches). This had nothing to do with the kitchen.
C
Curly
10 Jul 2017 22:32
We also have a window sill height of 104.5cm (41 inches) in the kitchen. The screed and flooring will be deducted from this, so the final height of the kitchen countertop will be around 90-91cm (35-36 inches). The countertop will then run directly to the window. Our builder also installed a thin foam insulation board on the window reveal.

Best regards,
Sabine
J
joegamble
10 Jul 2017 22:41
Our floor structure is thicker. In addition to screed, for example, there is also insulation and underfloor heating. That is why it is 20cm (8 inches). In your case, it would be “only” about 14cm (6 inches)…
C
Curly
10 Jul 2017 22:47
For us, it is 104.5cm (41 inches) minus 17.5cm (7 inches) floor structure = 87cm (34 inches), plus 3-4cm (1-1.5 inches) kitchen countertop, which totals 90-91cm (35-36 inches).

Best regards,
Sabine
77.willo11 Jul 2017 02:31
Just out of curiosity: Why do you prefer a specific parapet height?
C
Curly
11 Jul 2017 07:13
77.willo schrieb:
Just out of curiosity: Why do you want a specific parapet height?

For us, it’s so the kitchen countertop fits perfectly under the window. Otherwise, it wouldn’t matter to me. For the other windows, we simply chose a standard masonry height that’s easy to build with.

Best regards,
Sabine