Floor advice for period house. Suspended, solid or half and half?

johjames

I haven't been able to find a definitive answer as to the best way to proceed with the ground floor aspect of the renovation of our Victorian terraced house, hence I want to ask for your advice! Thanks so much!
1.We’re about to build a side infill/return extension and also had planned to replace the current concrete floor in the rear of the house as it’s been poorly done. This has led us to consider removing the suspended timber floor at the front of the house too and replacing the entire floor area throughout with a hardcore, sand blinded, dpm, insulation and concrete oversite build up. This will hopefully address issues with rodent ingress and different warm up times for ufh should we leave the suspended floor and also have concrete underfloor areas. The floor laid throughout will be engineered wood with ufh.
2.What are your views on doing this, as I’m worried about problems with damp occurring as the subfloor area will be solid and unable to breathe?
3.The other options would be a.making the entire floor throughout suspended with a breathable subfloor throughout or b.proceeding with the extension and rear floors in the concrete oversite finish and leaving the original floor suspended. This would of course be problematic in terms of the ufh warm-up times and cost. Would either of these options be preferable to the first?

Ganga

You could use full stops and paragraphs to make your post easier to read than a wall of text.

Heedtheadvice

Have a look at using a suspended concrete floor. The best of both worlds!


Consists of suspended reinforced concrete beams and the standard block infill between them. It is very easy and quick to build, add insulation, U floor heating, too concrete screed etc.


All components readily available, nice and solid floor results, but can be heavy to lift long ones during construction!


A quick search for 'concrete suspended floor' will return lots of results and info.

FreeBear

johjames wrote: »

I've looked at the option of using a limecrete foundation,

I have had contact with a few people that have used limecrete floors in period properties. A thick layer of foamed glass has provided ample insulation and has reduced the amount of moisture rising up through the slab - If you think about it, foamed glass provides a reasonable damp proof layer. Mixing in rubble, sand, and other building debris wouldn't be a good idea.

Victorian terrace houses are notorious for having very shallow foundations, so there will be a limit to how far down you can excavate. Without underpinning, you may not be able to go down much more than 6 inches. Test pits would need to be dug to ascertain the state of existing foundations.

Depending on how deep the void is under your existing floor is, a block & beam concrete floor could be installed. Although to meet current insulation requirements to satisfy building control, it is going to have to be quite thick.

johjames

Ganga wrote: »

You could use full stops and paragraphs to make your post easier to read than a wall of text.

Thanks Ganga. I will amend. You're absolutely right.

johjames

Thanks Heedthead. I've had a quick look and it looks like this method might be interesting to consider.

johjames

Sorry, I forgot to ask whether in your opinion, this would be easy to replace the current timber joists with? Thanks again

johjames

Thanks FreeBear, that's helpful.

ComicGeek

That sounds like a lot of work to replace the existing floor. A new beam and block floor with screed topping would be much heavier than the existing floor, so proper advice on the existing foundations is needed, Building Control will want to see these calcs. I very much doubt that you will get the whole floor build up less than 270mm with block, insulation, ufh pipes and screed on top, and I think it's minimum 225mm ventilation below. You'll need additional supports for the concrete beams.

Great for a new build extension, but a nightmare to retrofit into an existing room with inadequate existing foundations. I can't imagine that a structural engineer or Building Control would sign this off without major works to the existing foundations.

No reason why you can't get UFH to work with the existing suspended timber floor, will be much cheaper! Insulation between the timber joists, membrane over the top, and then boarding and UFH system over the top - lots of good UFH systems for this set up available.

Heedtheadvice

Ah yes, I humbly agree that foundations and available space could well be a problem for the existing part of the property.



A bit late for me to say but, really, professional advice should be sought!