Renovating Floor - Concrete vs Joist

[Vedspisen]

Going to tear up the old floor and lay a new one. The house has an old crawl space foundation and I'm contemplating between pouring concrete or installing new wooden joists. What is recommended, concrete or new wood?

There's a chimney in the middle of the house if that matters in the context.

I want warm floors that will last for many years to come. Tips and tricks, ideas, and thoughts are gladly received.

Thanks in advance!

 

[Pappa1986]

Going to tear up the old floor and lay a new one. The house has an old torpargrund and I'm torn between pouring concrete or installing new timber joists. What is recommended, concrete or new timber?

There is a chimney in the middle of the house if that matters in the context.

I want warm floors that will last for many years to come. Tips and tricks, ideas and thoughts are gladly received.

Thanks in advance!

Hey there.
It's always tricky with a torpargrund.
The idea with a torpargrund from the past was that it was fired up every day.
The chimney then warmed from underneath and spread through the foundation. In this way, moisture was kept at bay.
Therefore, it can be common to have moisture damage if you have a torpargrund.

Check with an expert on how to proceed, but tearing up all the floors and pouring a slab is probably preferable, though it is a heck of a lot of work. Maybe it could be possible to make a crawl space instead? Although that's just as much work.

 

[Vedspisen]

Hey.
It's always tricky with a crawl space foundation.
The idea with a crawl space foundation from the past was that it was heated every day.
Then the chimney heated from below and spread in the foundation. In this way, moisture was kept away.
Therefore, it can be common to have moisture damage if you have a crawl space foundation.

Consult with an expert on how to proceed, but tearing up all the flooring and casting a slab is probably preferable, although it is a lot of work. Maybe it could be possible to make a crawl space instead? Just as much work for that matter.

I've consulted with three different craftsmen and basically get three different answers: tear out and repair what's bad, tear out and build everything new, tear out and pour concrete. So it seems difficult with the expertise as there doesn't seem to be a definite answer. I'm prepared for the fact that it will be a lot of work, so that's okay. I just want it to be done properly right away without having to think about the floor again for a long time.

 

[justusandersson]

Not all craftsmen possess the technical skills (some do) required to solve this type of problem. It really depends on what you want to achieve. For an old-fashioned torpargrund to function, you need to both heat the chimney (in the winter) and limit the amount of insulation so that there's some heat leakage downward. Whether a floor is cold or warm depends more on the choice of floor surface than on the amount of insulation (and the absence of drafts). If you think this is a good option, you tear up the floor, replace what's bad, insulate it with a maximum of 15 cm of stone wool or similar, and put back the floorboards if they are in good condition.

If you want to upgrade to modern insulation standards, have underfloor heating, etc., you need to remove all the wood, excavate so you have space for draining material, insulation [there are various options for that execution], and then cast an insulated concrete slab on top. It’s not cheap, you could heat for the mice for quite a while for that money.

 

[Vedspisen]

Not all craftsmen have the technical competence (some do) required to solve this type of problem. It all really depends on what you want to achieve. For an old-fashioned foundation to function, it requires both firing the chimney (in the winter) and limiting the amount of insulation so that there is heat spillage downwards. Cold or warm floors depend more on the choice of floor covering than on the amount of insulation (and the absence of drafts). If you think this is a good option, you break up the floor, replace the parts that are bad, insulate it with a maximum of 15 cm of mineral wool or similar, and put back the floorboards if they are good.

If you want to meet modern insulation standards, have heating coils in the floor, etc., you will have to remove all the wood, excavate so you have space for draining material, insulation [there are variations of this setup], and then cast an insulated concrete slab on top of it. It's not cheap, you can heat for the mice for quite some time for that money.

Sounds reasonable. The next consideration is whether a modern concrete foundation is worth the effort on a house that has otherwise stood for almost 100 years and is otherwise in great condition. The current floor isn't moldy or bad in that way, it's simply worn out and lacks insulation (it's incredibly cold). If encapsulating the foundation in concrete, could issues like moisture possibly arise? Also, it seems many people use concrete in old foundations, so I guess there must be something positive in that?

 

[justusandersson]

The old stone foundation must be insulated from the concrete slab. It is a technically correct and good solution, especially if it involves large areas and more problems that need to be addressed. In your case, I think it seems like overkill. You will get far just by filling the trossbottnar with insulation. Regularly using the murstock during the winter months is essential.

 

[Vedspisen]

The old stone foundation must be insulated from the concrete slab. It is a technically correct and good solution, especially if it concerns large areas and more problems that need to be addressed. In your case, I think it seems overkill. You'll get a long way just by filling the joist bottoms with insulation. Using the chimney regularly during the winter is essential.

Thanks for the response! I think I'll break it all up so I get a complete picture of the situation and make a decision based on that.

If I have interpreted the whole thing correctly (after reading most things online and consulting), there seem to be pros and cons with both options. The advantage of new timber: relatively easy to implement, easy to repair in case of problems like water leaks or similar, soft and old-fashioned character that breathes.
Advantage of concrete: straight and solid foundation, suitable for underfloor heating, good insulation capability, maintenance-free.

 

[Pappa1986]

Thanks for the response! I think I'll go ahead and break it all down so I get a complete picture of the situation and make a decision based on that.

If I've understood it correctly (after reading most things online and consulting), it seems there are pros and cons with both options. Advantage of new timber: relatively easy to carry out, easy to repair in case of problems like a water leak or similar, soft and old-fashioned character that breathes.
Advantage of concrete: straight and solid foundation, suitable for underfloor heating, good insulation properties, maintenance-free.

Please take a picture once you've removed the floor so we can follow along with the renovation.

 

[Vedspisen]

Feel free to take a photo when you've removed the floor so we can follow along with the renovation.

Absolutely, I will do that. I will start this weekend, so I will document and upload as I go along.

 

[justusandersson]

Both options have advantages and disadvantages. The concrete option will be significantly more expensive and have more far-reaching consequences. It needs to be designed so that nothing is missed.

I think it's a good strategy to start by breaking up the floor and getting an overview.

 

[JA”Snabbe”]

I backed out of a house purchase due to a damp crawlspace foundation. It's completely impossible to fix such a foundation if you want to live modernly and not "heat for the mice." I would have poured a slab; it secures the house's value, and you'll be able to sell it in the future.

The house I looked at had a foundation in natural stone, not crawlable, full of cut-off logs supporting the joists. The foundation was also divided into different sections that were separated from each other, so during the inspection, you only saw a small part of the foundation.

 

[useless]

Have you considered the option varmgrund?

 

[Vedspisen]

Have you considered the option of a warm foundation?

No, actually not. I've interpreted the warm foundation as a greater risk than the traditional crawl space foundation (right or wrong?).

I've understood that it's an attractive construction in many ways, but purely looking at the construction straightforwardly seems a bit risky over time. I don't know if it's worth the hassle in relation to the traditional, simply put. But feel free to share your views on this, they are welcome.

 

[Pappa1986]

I believe that a really good crawl space is a good replacement for the torpargrund.

That way you have control and can address it more easily if problems arise.

 

[JA”Snabbe”]

I think that a really good crawl space is a good replacement for the torpargrund.

Then you have control and can fix it more easily if there would be any problems

Unfortunately, you can't always convert a torpargrund to a crawl space. In my case, the foundation was full of gigantic stones. So breaking up the floor and digging out to then create a risky construction again instead of pouring a slab that becomes problem-free? Then the choice would have been easy, luckily I avoided buying that problem. But if you already own the problem, I would have poured a slab, no doubt. If you're going to undertake a colossal task, you're better off eliminating future problems. But we are all different and have different acquaintances, etc., which can influence decisions.