Level basement floor

[Snigla]

A question for those of you who know more than I do

If you have a basement, with an uninsulated slab and want to insulate on the "top" before laying the flooring material you want.. how do you do it the best way? I know the principle.. i.e., when we did it ourselves.. we used something like Platon mat underneath.. then "floating construction" with 5 cm foam (for flooring then.. or yes, higher load-bearing capacity) and then particle board + finish)

But my question is rather about if you want an even more stable floor for heavy things.. how can you do that? if you necessarily want insulation on top... can you use some kind of framework?

I was wondering if you could solve the construction in the same way as you sometimes do in basement walls.. i.e., steel studs with wood studs inside (i.e., they don't come in contact with moisture).. can that work the other way around on the floor? i.e., you place a steel stud at the bottom and a wood stud inside it... and then insulate with foam and particle board + finish?

Or is it a big "no no"...

Tips? Ideas?

Thanks in advance
Best regards Sandra

 

[imported_Byggaren]

The important thing is to create an air gap between the concrete slab and what will be on top of it. You can, for example, use regular wooden battens combined with Knutson wedges (made of plastic) that do not transfer moisture to the battens.

How you make the floor is another matter. You will likely need to lay some type of board (8 mm oil-impregnated hardboard if you're using foam insulation, or double 12 mm asphalt board if you're using standard mineral wool) at the bottom under the battens (it will be a bit fiddly to make it work) or nail a plank on the flat side under them with protruding support and lay the board between them (it is recommended because you can work from above the entire time). On the board, place insulation up to the top of the battens and then board again (22 mm chipboard), but then you need to consider that the warm room air might penetrate the insulation if you don't install a plastic film under the chipboard.

Then make sure to connect the air gap under the floor with the air in the room. The simplest way is to leave the chipboard 5-7 mm from the wall and cover the gap with a Syninge ventilated skirting board. __________________________ Builder

 

[Koorina]

Platon with foam plastic & chipboard should work well, if you want a more stable floor increase the thickness of the chipboard.

An alternative is also Granab with e.g. 38mm chipboard if extra stability is needed, a good alternative if the slab is not perfectly straight (avoids using leveling compound).

Vented baseboard or ventilated.

 

[Snigla]

Korrina:

Granab is the equivalent of Nivells system, right? When we laid our form of floating floor it felt like it would give in if we placed something like a piano there or similar..we don't want any bouncy floors in any way (hence the thought of using beams..which helps to support it)

Best regards, Sandra

 

[Snigla]

imported_Byggaren:

So you can't do it the same way as with the floating floor.. i.e., lay the cellplast directly on platon type.. and then build on top of it.. and use ventilated baseboards? *wondering if I missed something in your text*

Best regards, Sandra

 

[imported_Byggaren]

Since you wanted a silent floor that supports a bit more than floating floors and therefore wanted a raised floor, I responded to that question concerning raised floors.

Of course, it's just as good to install a floating floor if you choose Platon at the base against the concrete to create the air gap, then a better quality foam insulation of some kind with high density (which insulates worse), a plastic foil (to avoid the squeaking between the foam and the underside of the 22 mm particle board floor and at the same time serve as a moisture barrier). But you should expect that it will flex more in a floating floor than in a raised floor because there will inevitably be compression in both Platon and the foam under heavy loads.
___________________
Byggaren

 

[Snigla]

imported_Byggaren:

You answered the right question before hehe (thanks!).. I wanted to explore just the raised floor part (we've laid floating floors before.. and I perceived it as hm "weaker".. if you have a lot of weight in certain spots - but that's just a personal opinion).

But what I was wondering was if you couldn't have the same "base".. even if you choose to use beams.. i.e. have the Platonmat in the bottom (moisture protection?).. and insulate with Styrofoam between the beams so to speak (maybe it's absolutely not possible to do it that way due to something.. but that's why I'm asking.. because I don't know )

Sorry for complicating my question..
Thanks for the replies!!
Best regards, Sandra

 

[imported_Byggaren]

---
But what I was wondering was if you couldn't have the same "bottom".. even if you chose to frame.. that is, have the Platon mat at the bottom (moisture protection?).. and then insulate with foam plastic between the frames so to speak (maybe it's absolutely not possible to do that because of something.. but that's why I'm wondering.. because I don't know )

---

You mean putting Platon on the concrete slab between the frames? Yes, that can also be done as an alternative to 'crawl space' with a board. The wedges (if the concrete slab is somewhat even) don't need to build more than the knobs on the Platon mat are high.
________________
Byggaren

 

[wedge73]

With the risk of being called stupid...

Can someone explain what the problem would be with placing a moisture barrier like plastic at the bottom, insulation on top, and finally casting the finished floor on top.

Why bother with an air gap?

Is there a difference if there is concrete under the insulation or just soil?!!

I understand that there is an advantage with a capillary-breaking base, read gravel/leca, but as far as I know, foam insulation is considered just that..

Wondering....

 

[imported_Byggaren]

With the risk of being declared an idiot...

Can someone explain what the problem would be with placing a moisture barrier like plastic at the bottom, insulation on top, and finally casting the finished floor on top.

Why complicate with an air gap?

Is there a difference if it's concrete under the insulation or just soil?!!

I agree that there is a benefit with a capillary-breaking substrate, read gravel/LECA, but as far as I know, the foam plastic insulation is considered just that..

Wondering...

This is what the original poster wrote in their first post:

"But my question is rather if you want an even more stable floor for heavy things.. how can you do that? if you necessarily want insulation on top... can you frame in some way?"

That's the question I've been answering the whole time.

Your alternative can of course also be performed. The main thing is that any ground moisture through the current concrete slab does not continue upwards into the floor.
_____________
The Builder

 

[wedge73]

Since you wanted a solid floor that supports a bit more than floating floors do and therefore wanted a raised floor, I answered the question regarding a raised floor.

It is of course equally possible to lay a floating floor if you choose Platon at the bottom against the concrete to get an air gap, then a better quality foam plastic of some kind with high density (which insulates worse), a plastic film (to avoid squeaking between the foam plastic and the underside of a 22 mm chipboard floor and also serve as a moisture barrier). But you have to expect that it will deflect more in a floating floor than in a raised floor since there will inevitably be compression in both Platon and the foam plastic under heavy load.
___________________
Byggaren

What I understand is that it concerns a more solid form of floor than floating...

My thought was that it would be a more solid and somewhat less complicated construction if you exclude the Platon mat and the chipboard and instead cast.

A big question mark is what benefit the Platon mat has the possibility to do; it requires, in that case, a ventilating air gap around along the walls that becomes less effective the thicker insulation is used.

Similarly, there aren’t very many m2 that the Platon mat can ventilate without the help of electric fans or equivalent.

One problem with casting is the height, but if there is room for Platon, insulation, and chipboard, it might work.

 

[ylven]

wedge73: the difference with concrete underneath instead of just ground, is that the concrete to some extent transports moisture. So there's a risk that the moisture will instead go up into the walls.