Hello to all home builders and renovators.
I would like to install a plastic window on my ground floor. The window installer said that for measuring, he needs the rough opening in the wall already prepared to produce the window. I believe the opening can also be made accurately afterward, so I wouldn’t have a hole in the wall for 5 weeks.
Now I would like to saw a cutout in the masonry. I plan to fill the cavities of the hollow concrete blocks with mortar to ensure a solid installation of the window. The installer mentioned that in older buildings, these cavities are usually just filled with foam and that works fine.
However, I would like to install a rigid insulation board made of pressure-resistant extruded polystyrene (XPS) in the reveals as an insulating layer. At the hardware store, these XPS boards are available in thicknesses of 20/30/40/50mm (0.8/1.2/1.6/2 inches). Does anyone have experience with how thick the insulation in the reveal should be for triple-glazed windows? My intuition is to use 30mm (1.2 inches) boards.
I would be very grateful for any tips and suggestions.
Best regards, Bob-Bau75
I would like to install a plastic window on my ground floor. The window installer said that for measuring, he needs the rough opening in the wall already prepared to produce the window. I believe the opening can also be made accurately afterward, so I wouldn’t have a hole in the wall for 5 weeks.
Now I would like to saw a cutout in the masonry. I plan to fill the cavities of the hollow concrete blocks with mortar to ensure a solid installation of the window. The installer mentioned that in older buildings, these cavities are usually just filled with foam and that works fine.
However, I would like to install a rigid insulation board made of pressure-resistant extruded polystyrene (XPS) in the reveals as an insulating layer. At the hardware store, these XPS boards are available in thicknesses of 20/30/40/50mm (0.8/1.2/1.6/2 inches). Does anyone have experience with how thick the insulation in the reveal should be for triple-glazed windows? My intuition is to use 30mm (1.2 inches) boards.
I would be very grateful for any tips and suggestions.
Best regards, Bob-Bau75
B
Bob-Bau755 Feb 2022 20:3111ant schrieb:
So, what is it now, basement or ground floor?
The basement might be made of aerated concrete blocks, but above it is a 1975 Neckermann, presumably from Streif, which is not aerated concrete (?) Yes, the basement is the ground floor embedded in the slope, with 50% of the exterior insulated and the rest inside the slope. Above the ground floor is indeed the Streif house you mentioned 🙂.
My idea was to cast a concrete lintel above the window, then cut out the reveals and smooth them with masonry mortar. After that, I would like to use rigid foam boards, 3-5cm (1–2 inches) thick, as reveal insulation.
Now I’m not sure if the insulation should be installed only on the sides or also on the top and bottom of the reveal?
After that, the window installer can fit a window with an external roller shutter, preferably RAL-compliant if possible.
Best regards and thanks for your help.
B
Bob-Bau755 Feb 2022 20:33Durran schrieb:
Very risky without a lintel. Definitely don’t do it.
So, install a lintel, then create the window opening. Afterwards, plaster the wall evenly. Insert the window. Do not use expanding foam. The opening should be 2–3 cm (about 1 inch) larger all around than the actual window. Insert compression tape between the wall and the window. No expanding foam.
Apply breathable window sealing tape on both the interior and exterior sides of the window. Then, stick 3 cm (1¼ inches) thick Styrodur insulation boards on both sides. On top of that, apply the window connection tape and plaster the window in.
This is how a proper RAL installation of a window is done, not otherwise.
People buy expensive windows, but then the wall connection is done incorrectly. Even the best window with the best insulation values is useless if installed wrongly. Using expanding foam in this case is completely wrong.
So if anyone notices windows being foamed in on their construction site, they should intervene immediately. Yes, that was actually also my idea of how a window installation should be done, especially for a window that is not just a standard DIY store model. I will bring this up with the window fitter next week during the measurement.
Thank you very much for your help.
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