Kitchen Floor Half Concrete (ventilation)

I recently purchased a 1907 mid-terrace house which unfortunately has cement render to the rear exterior. The kitchen needs re-plastering as there is a lot of crumbling and damage to the kitchen walls on one side. (The other side has Artex)

The kitchen floor is a mixture of concrete and raised timber. I have ensured there is good airflow to the sub-floor in the way of air bricks; however I feel the concrete floor has no ventilation (no air bricks on this side) causing trapped moisture to rise up the walls causing damage. I have already dug up the sloped concrete slabs outside and replaced with shingle but the builder only did this to a depth of 50mm. On the side of the kitchen which has bad walls, the external render here reaches to the ground. The toilet room beside the kitchen has a bit of mould on the wall and this is also a concrete floor with the external render touching the floor.

Before I get a kitchen put in, I would like to fix the floor and make it level. What is a cost effective way to do this? What are my options? I was thinking the following:

1. Get the concrete dug up and replaced with a breathable concrete like limecrete then screed over the entire floor
   
   
2. Get the concrete dug up and replaced with wooden floor boards (to match the other side)
   
   
3. Do something else? So the concrete side is breathable
   

I would appreciate any help. I have been quoted just under £1000 to do something similar to option 2 (kitchen only) but mention of a DPC was included (is this needed and recommended? Surely a well ventilated sub floor should suffice?)

Once the floor is fixed what type of kitchen flooring should I have? Does it have to be breathable? If so then vinyl isn't suitable?

You can’t ventilate concrete floor, can’t imagine why you want to .

dont do any more first fixing until you've hacked off all the plaster you intend to take off - any plaster with damp signs needs hacking off.
dont store materials in areas where you intend to work.
do you have a planned drawing of the new kitchen?



why not post pics of the outside of all the external walls at the rear elevation - show all air bricks. and a pic of the front elevation at ground level?
any other concrete floors in the house?
Its probable that your kitchen/toilet concrete dont have DPM/membranes below them?
are the joist tails in your pic rot free?
have you been under the suspended floors yet?
on the outside and inside the walls have you identified the position of any DPC?

foxhole said:

You can’t ventilate concrete floor, can’t imagine why you want to .

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I know that. That's why I want to provide ventilation as the subfloor has none. I think removing the concrete is what is needed.

bobasd said:

dont do any more first fixing until you've hacked off all the plaster you intend to take off - any plaster with damp signs needs hacking off.
dont store materials in areas where you intend to work.
do you have a planned drawing of the new kitchen?



why not post pics of the outside of all the external walls at the rear elevation - show all air bricks. and a pic of the front elevation at ground level?
any other concrete floors in the house?
Its probable that your kitchen/toilet concrete dont have DPM/membranes below them?
are the joist tails in your pic rot free?
have you been under the suspended floors yet?
on the outside and inside the walls have you identified the position of any DPC?

Click to expand...

I have rough plans of the kitchen yes but nothing concrete. I don't have the funds yet to buy a kitchen. Need plastering done and get the floor sorted first. I've uploaded some photos. The back of the house (kitchen, hallway and toilet room are concreted. No air bricks outside on this part but render down to the ground. I've since lowered the ground a bit so maybe that is all I need to do. Where the timber floor meets the concrete there is a medium sized hole in the subfloor dwarf wall, that's the only ventilation the concrete has from what I can see.

Is it a good idea to restore this floor to timber before I put a kitchen in? Or simply removing some of the render outside and possibly there may be an air brick there?

Regarding dpm. I don't know if my property has it. How do I tell? Can you see from the photos?

The joist tails were fine apart from 3 which were rotten when I purchase the property and have been replaced. I've checked the joists for weeks now and even during heavy rain the joists are completely dry. I think lowering the ground has helped.

i dont know enough to advise on replacing or leaving the concrete floor area?

how you would plaster the walls with all that cabling and piping jumble i dont know.
you have to work to a plan or you will be constantly going back over previous work - eg modern kitchens tend to have a separate ring that needs first fixing to a plan.

can you see under the concrete or is it a solid slab sitting on the ground?
i'm confused with "dwarf wall" and the "only ventilation" - maybe you can take pics showing these things?
The DPM is a plastic sheet that sits under any concrete floor - i dont see any DPM where your concrete floor meets the wall ie below or behind the skirting. the hallway and WC will be the same.

the front air brick appears to be too high - it should be ventilating the sub-area below the suspended floor. is that the only front air brick?
the rear render stops well high of the ground, as it should - but it doesn't have a Bellcast.

bobasd said:

i dont know enough to advise on replacing or leaving the concrete floor area?

how you would plaster the walls with all that cabling and piping jumble i dont know.
you have to work to a plan or you will be constantly going back over previous work - eg modern kitchens tend to have a separate ring that needs first fixing to a plan.

can you see under the concrete or is it a solid slab sitting on the ground?
i'm confused with "dwarf wall" and the "only ventilation" - maybe you can take pics showing these things?
The DPM is a plastic sheet that sits under any concrete floor - i dont see any DPM where your concrete floor meets the wall ie below or behind the skirting. the hallway and WC will be the same.

the front air brick appears to be too high - it should be ventilating the sub-area below the suspended floor. is that the only front air brick?
the rear render stops well high of the ground, as it should - but it doesn't have a Bellcast.

Click to expand...

If I lift the timber floorboard and look towards the concrete I can see brickwork for a dwarf wall (the subfloor has little brick walls at certain distances). In the brick wall I believe is a hole. That's the only entry I see for air to pass. I've attach a picture.

Yes the render is well above the ground at parts but where the back of the kitchen is and toilet the render here touches the ground. Can a bell cast be retrofitte?

All air vents go into the sub floor including the front elevation. There is also an air vent under the front door.

Anyone? So what should I do about the floor? To get someone in to help I should know what the best approach is.

No replies. Should I put this into the builders section?

the concrete floor looks cracked and damp. It is not tiled or terrazzo so I suspect not original. If not original it was probably laid to replace a rotted floor and conceal the damp.

If you dig it out, you can incorporate a dpm, insulation, and also relay the hundred-year-old water pipe which is quite likely leaking. You will probably find the hundred-year-old drains are leaking as well, but that's outdoor work. All that will cut or cure your dampness and reduce heat loss.

your new water pipe can be 32mm plastic which will give you vastly improved flow and allow you to have worthwhile showers from an unvented cylinder (or a combi if you like that sort of thing)

My preference is for suspended wooden floors, but even if you decide to have concrete, you can incorporate a duct to help ventilate the wooden floor behind. Dig out all that rubbish and clean out the airbricks. If it is bare earth you can add a DPM and a bit of concrete or shingle to hold it down.

I think I'm going to get quotes to restore it to solid suspended floor. Obviously difficult to say but what is a fair price to get this done? Ballpark figure

I've been quoted just under £1700 to restore the concrete to a suspended timber. Is this too much? I'm trying to get more quotes but builders are letting me down with popping over.