Old house/new floor - choices choices

[SiH]

Afternoon all.
We have a mid 19th century cottage with a floor that needs replacing due to damp and woodworm.
It's currently a suspended wood floor with just a single airbrick. Due to the layout of the house, it's unfortuantely no viable to fit another airbrick.
As a result, we need to make some decisions about what to replace the floor with. The room in question has some mild damp in teh walls tha tis causing paper to peel. The walls can, if nieccessary, be stripped to bare brick, and some sort of treatment applied to tie in with new floor choice.

The way I see it, our choices are:
Another suspended wood floor: Still have issues with damp due to no potential for another air brick - lifespan limited, still get damp issues. However, 'inkeeping' with the property.

Solid concrete: Possibility for a lot of good quality insulation, which can only be a good thing. Potentially cheaper as more DIY-able to a non chippie such as myself? However, the state of the damp course is not known and is presumed to be slate - not sure if we can tie in the damp proof membrane for the new floor with this. Concerns about pushing damp up the walls if no DPC present.

Suspended concrete block floor: potentially cold, no insualtion, worries about not helping with damp.

Is there anything else I'm missing? Any of you experts have any advice what we should be choosing?
Thanks
Si

 

[mointainwalker]

The most important thing in my view is to find and cure the current damp-problem rather than thinking a new floor will automatically solve it as this is unlikely.

As for your new floor, well I like wood-floors anyway, so I am naturally predisposed to that , especially , as you say, it is in character with the house. It would also be cheaper to insulate than a solid floor as you could stuff fibre-wool in between the joists.

Leaving that aside, putting in a solid concrete floor could potentially cause new damp problems by forcing moisture up into the walls as you mention.

Not sure why you see the concrete as more DIY'able than the wood. Having done both as a DIY'er, I found wood easier and much more pleasant to work with. Depending on your taste, you may also be saving yourself both work and cost by making the wooden-floor , the finish i.e. no carpet/tiles etc

 

[SiH]

Thanks
The current damp problem has been diagnosed from non destructive testing by an independant damp speicalist (not a 'free quotation' type place) as being most likely to be caused by damp course bridging. However, we're not 100% sure yet as we haven't hacked off the plaster at a low level to check for a DPC. It's been assumed we have a slate DPC, but if not, I guess I need to research our options.

For insulation on a wood floor - I had presumed that, even if insulation were suspended, the air gap underneath would be less preferable to a mountain of insulation that we could install with a concrete floor.

The main issue is that as far as we can see there's no way to add another sub floor vent, so we'd be facing the same issues in the future as we do now, due to inadequate ventilation.

Regarding ease of install - I'm not sure I'd trust myself to install a wood floor due to the craftsmanship needed, however a concrete floor seems on the face of it an easier solution, with backfilling, sand, and insulation all do-able by myself (therefore greatly reducing cost), and just getting a pro in to do the slab. Have I got this totally wrong?

 

[mointainwalker]

so we'd be facing the same issues in the future as we do now, due to inadequate ventilation.

If the damp is being caused by a bridged DPC, what issues are there with the ventilation ?

How deep is the underfloor void ? Obviously if it's very deep, it will require lots of concrete to fill it. You will need to use polystyrene/PIR insulation under the concrete which is probably 5 to 20 times more expensive than fibre-wool if the latter is still being subsidised ( 3 to 8 if not.).

Do you know if your joists need replacing ? If not , or even if it's only one or two, I would certainly see the wooden floor as much easier and cheaper, your decision though.