ᐅ Loose-fill insulation around pipes vs. insulation boards

Hello everyone,

I have a question regarding loose-fill insulation over heating pipes.

On the concrete slab in the ground floor, we have the following 22cm (8.7 inches) floor structure, from bottom to top:

• ~0.5cm (0.2 inches) waterproof membrane
• 6cm (2.4 inches) + 5cm (2 inches) polystyrene insulation boards
• 3cm (1.2 inches) insulated fixing mat
• 6cm (2.4 inches) screed with underfloor heating pipes
• 1.5cm (0.6 inches) floor coverings

The 6cm (2.4 inches) + 5cm (2 inches) insulation boards are used because most of the pipes on the floor slab are 4–6cm (1.6–2.4 inches) high, and we wanted to lay the second layer of insulation boards completely continuous. Water and heating pipes should be leveled with Mehabit-bound loose-fill insulation up to the top edge of the first layer.

However, on the slab, there are also two heating pipes with insulation sleeves that are 8cm (3.1 inches) high. How should we proceed here?

Current plan: We will lay both layers up to the pipes, fill up to 11cm (4.3 inches), and then simply place the fixing mat on top.

Is this okay, or should a more rigid insulation board be installed under the fixing mat in this area?

Good luck

Tushan79 schrieb:

Hello everyone,

I have a question regarding insulating fill around heating pipes.

We have the following 22cm (8.7 inches) floor buildup on the concrete slab at ground level, consisting of (from bottom to top):

• ~0.5cm (0.2 inches) waterproof membrane
• 6 + 5cm (2.4 + 2 inches) Styrofoam insulation boards
• 3cm (1.2 inches) insulated stapling mat
• 6cm (2.4 inches) screed with underfloor heating pipes
• 1.5cm (0.6 inches) floor covering

The 6 + 5cm insulation boards are because most pipes on the slab are 4–6cm (1.6–2.4 inches) high, and we wanted to lay the second layer of insulation boards continuously throughout. Around the water and heating pipes, bonded fill with Mehabit up to the top edge of the first insulation layer is intended to level out the surface.

However, on the slab there are also 2 heating pipes including insulation sleeves with a height of 8cm (3.1 inches). How should we proceed here?

Current plan: We lay both layers of insulation boards up to the pipes, fill up to 11cm (4.3 inches), and then simply place the stapling mat on top.
Is this okay, or should a more stable insulation board be placed under the stapling mat at this spot?

Good luck

I initially had a full 5cm (2 inches) insulation layer with WLG 032 installed continuously. In the second insulation layer above (laid perpendicular to the first layer), also with WLG 032, the water pipes are located, naturally insulated. On this second layer, the 3cm (1.2 inches) stapling mat is installed.

Simply lay the stapler mat on top. You can be completely relaxed (unless you need 30cm (12 inches) wide channels for the heating pipes).

Hausbau 55 schrieb:

I first had a complete 5cm (2 inch) insulation layer with a thermal conductivity of 0.032 W/mK installed without any breaks. The water pipes, naturally insulated, are placed in the second insulation layer above that (laid perpendicular to the first layer), also with a thermal conductivity of 0.032 W/mK. On this second layer, the 3cm (1¼ inch) staple mat will be installed.

That doesn’t help me regarding my question. The 8cm (3 inch) heating pipes are already in place. Essentially, my question is how to level the 3cm (1¼ inch) up to just below the staple mat.

Benutzer200 schrieb:

Just place the staple mat on top. You can be completely relaxed about that (unless you need 30cm (12 inches) wide channels for the heating pipes).

So you still have to level the 3cm (1¼ inches) with screed or filling material, right?

Since we’re on the subject: actually, I have 5-6cm (2-2½ inches) high flat ducts from the ventilation system on the upper floor.
There is 6cm (2½ inches) plus 2cm (¾ inch) insulation planned. The ducts are about 15cm (6 inches) wide, and in one spot there are even 2-3 side by side.
I hope I can place the 2cm (¾ inch) insulation evenly on top. If not, wouldn’t using leveling material over a wide area be rather problematic?

Tushan79 schrieb:

So, that means to level out the 3cm (1.2 inches) with filling material, right?

Yes, go ahead and pour it in.

Tushan79 schrieb:

I hope I can lay the 2cm (0.8 inches) insulation evenly on top there. If not, would the filling material for leveling the surface be a problem?

No, no problem.