Hello everyone,
We have several balconies with FPO membranes.
Construction:
200mm (8 inches) concrete slab
120mm (5 inches) PU insulation - WLS 0.23, 120 kPa
EPS sloped insulation boards - WLS 0.35, 150 kPa
Separation layer (polyester fleece)
FPO membrane
I am currently considering which type of flooring to use here. At the moment, I am leaning towards either terrace slabs or WPC decking boards. Both options would be installed with pedestal supports.
My questions regarding the terrace slabs:
1. These often have a thickness of 2cm (0.8 inches) and come in sizes like 60x60 cm (24x24 inches), 80x80 cm (31x31 inches), 60x40 cm (24x16 inches), or 120x60 cm (47x24 inches). Are these thinner slabs prone to breaking when they are supported above pedestals and thus have hollow spaces underneath?
2. Would the flooring feel spongy because of the insulation layer underneath, making terrace tiles feel odd underfoot? Has anyone had experience with this? I think this would be less noticeable with WPC decking boards.
We have several balconies with FPO membranes.
Construction:
200mm (8 inches) concrete slab
120mm (5 inches) PU insulation - WLS 0.23, 120 kPa
EPS sloped insulation boards - WLS 0.35, 150 kPa
Separation layer (polyester fleece)
FPO membrane
I am currently considering which type of flooring to use here. At the moment, I am leaning towards either terrace slabs or WPC decking boards. Both options would be installed with pedestal supports.
My questions regarding the terrace slabs:
1. These often have a thickness of 2cm (0.8 inches) and come in sizes like 60x60 cm (24x24 inches), 80x80 cm (31x31 inches), 60x40 cm (24x16 inches), or 120x60 cm (47x24 inches). Are these thinner slabs prone to breaking when they are supported above pedestals and thus have hollow spaces underneath?
2. Would the flooring feel spongy because of the insulation layer underneath, making terrace tiles feel odd underfoot? Has anyone had experience with this? I think this would be less noticeable with WPC decking boards.
S
Singelküche7 Jul 2025 17:4616/32 was always used on flat roofs and is definitely too coarse for this purpose.
A protective building membrane would always be mandatory for me.
22 m2 (240 sq ft) about one ton of gravel
Aluminum is lighter
A protective building membrane would always be mandatory for me.
22 m2 (240 sq ft) about one ton of gravel
Aluminum is lighter
Singelküche schrieb:
16/32 was always used on flat roofs but this is definitely too coarse for this.Too coarse for laying terrace tiles. What alternative gravel size should be used then? My roofer said that with gravel and terrace slabs (instead of pedestal supports), water drainage is also worse. But with 16/32 gravel, there would normally be enough space between the stones for water to drain.
I spoke again with my roofer. He said that if I want to lay the terrace slabs/tiles without pedestals, then 16/32 crushed stone is not suitable, but rather gravel. Under the gravel, definitely use geotextile fabric or protective building mats. Due to the gravel, water wouldn't drain as well. He still recommends pedestals, either the self-leveling ones or, even better, the ones with the aluminum system.
Status / Info: I ordered some self-leveling pedestal supports for testing purposes. Let’s see if they are more comfortable to work with.
Regarding installation without pedestal supports and water drainage:
Would it be possible to lay the patio tiles directly on 16/32 gravel (16/32 mm (0.6/1.3 inches))? That would at least improve the water drainage compared to using crushed stone.
Regarding installation without pedestal supports and water drainage:
Would it be possible to lay the patio tiles directly on 16/32 gravel (16/32 mm (0.6/1.3 inches))? That would at least improve the water drainage compared to using crushed stone.
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