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Damp Proof Membrane costs

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charlie123

Newbie
Hi all
I’m in the process of purchasing a property and the homebuyers report from the surveyor has indicated high level of damp in the kitchen area which is most likely caused by not having a membrane as the was built in 1950s.

If the damp is in the kitchen (back of the house) and damp has been detected in both other rooms on the ground floor, l assume that all the concrete flooring will need to be removed and replaced

If this area is about 40metre squared - what sort of price am l looking at to knock off from the asking price. I’m assuming it’s goimg to cost at least 6/8k.

Has anyone had the unlucky experience of having the concrete removed and the membrane laid and if so what sort of costs will l be looking at...

Also any recommendations for someone in the midlands/Birmingham area that could potentially give me a quote

Many thanks
Charlie
 
charlie123 said:
Hi all
I’m in the process of purchasing a property and the homebuyers report from the surveyor has indicated high level of damp in the kitchen area which is most likely caused by not having a membrane as the was built in 1950s.

If the damp is in the kitchen (back of the house) and damp has been detected in both other rooms on the ground floor, l assume that all the concrete flooring will need to be removed and replaced

If this area is about 40metre squared - what sort of price am l looking at to knock off from the asking price. I’m assuming it’s goimg to cost at least 6/8k.

Has anyone had the unlucky experience of having the concrete removed and the membrane laid and if so what sort of costs will l be looking at...

Also any recommendations for someone in the midlands/Birmingham area that could potentially give me a quote

Many thanks
Charlie
Click to expand...

Hello Charlie, first things first, where has the surveyor said the damp is located?
there are several types of damp proof membranes - floors have a polythene sheet underneath them, often insulation too, and this is the normal construction of a modern floor, but not something you would expect to see in anything built before the 1980's - anything after that should be OK.
If you mean damp in walls, and the house was built in the 50's, as you state, the cause will almost certainly be (and I do this every day) the plaster will be too low - if plaster goes to the floor (behind the skirting board) this wlll 99% certain to be the cause of the 'damp'.
All you need to do to verify this is take a piece of skirting board off in an affected area and check how far the plaster goes down - if there's not at least a 50-60mm gap between the bottom of the plaster and the floor, this is the cause of the problem.
If the floors are indeed damp, which I find hard to believe, you may be able to get them asphalted, which is a damp barrier and also a finished surface for around £25 per m2 for small areas - cheaper for a full house
 
charlie123 said:
Hi all
I’m in the process of purchasing a property and the homebuyers report from the surveyor has indicated high level of damp in the kitchen area which is most likely caused by not having a membrane as the was built in 1950s.

If the damp is in the kitchen (back of the house) and damp has been detected in both other rooms on the ground floor, l assume that all the concrete flooring will need to be removed and replaced

If this area is about 40metre squared - what sort of price am l looking at to knock off from the asking price. I’m assuming it’s goimg to cost at least 6/8k.

Has anyone had the unlucky experience of having the concrete removed and the membrane laid and if so what sort of costs will l be looking at...

Also any recommendations for someone in the midlands/Birmingham area that could potentially give me a quote

Many thanks
Charlie
Click to expand...
Hi Charlie
As Pabs has already said its more than likley that it has been plastered down to the floor "bridging" the damp course the fact that it has concrete floors suggests that the old floors has been removed ( floating wooden or ash with quarry tiles) check online to see when the house was sold last because it may have been done for mortgage retention if this was the case then building control would have been involved and it defo will have a DPM in . Or worse case senario it is suffering from rising damp which means hacking off the plaster back to brick upto 1meter injecting chemicals and re instating the plaster etc
 
Thanks for the detailed reply
This is taken from the report - just copied and pasted it :)

Damp Proof Course : During the course of construction it appears the house has been provided with a slate DPC bed in cement mortar which stands just about 1 1/2 brick courses above ground level. Most areas seem to be fairly secure although we did find instrumental evidence of high moisture levels to the back wall of the rear sitting room as well as along the side of the hallway where it appears the DPC has probably fractured and malfunctioned. There are also signs of damp beneath the concrete floor slab in the kitchen area beneath the thermal plastic tiles. Both areas will therefore need to be examined by a timber and damp specialist contractor and an estimate obtained for the cost of injecting a new chemical DPC as well as installing a damp proof membrane beneath the solid floor slab. (Condition rating 3)

If you can put that in simple terms to be and estimated cost that would be fantastic :)

Would l need to replace the whole of the concrete flooring as l assumed it doesn’t have a membrane and then get a damp proof course sorted for the rest of the adjacent walls

The house has never been sold before as the lady that purchased the property in the early 1950s has passed away last year. It’s been given to the children as part of the will so they are selling it.
 
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I do this for a living.

There is no need to remove the concrete floor in situations like this the effected walls would be Hacked off minimum 1m high, injected with a damp proofing cream. Then the brick would get a waterproof slurry painted on the brick from 500mm high down to floor, then onto concrete floor about 6 inches. To form a waterproof barrier. 2 coats.
Sand and cement with a salt retardant/waterproofer added would be floated onto the wall. Once all walls are floated (1-2 days dependant on job size) it would get skimmed.

Feel free to message me with any questions
 
Thanks for the info guys
I just need to work out what it’s gonna cost me for sorting this out

Damp course for walls
Damp course for kitchen or other floors if required


Kitchen is 2.5m by 3m

Lounge is 4.11 by 3.33

Dining is 2.39 by 3.07

Hall way 2.5m by 2.1m


Will get this knocked off the agreed price as an estimated cost

Thanks in advance :-)
 
it's not possible to estimate something like this remotely.
For a start, to dampcourse the kitchen as @liamt explained above, the walls need hacking off to bare brick a 1m high and replastered afterwards.
This means all the kitchen units, worktops and appliances will have to come out and reinstalled, providing they don't fall apart.
The skirtings right through the house will possibly (probably) need renewing as part of the job.
So you'd need either a new kitchen or a good joiner to take out and reinstall the existing, also replumb the sink back in.
If the damp is in the floors these could be asphalted over (a type of fine bitumen that goes on an inch thick over the entire floor and sets very hard) but to do just the kitchen would leave a 1 inch step up into the room
 
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Thanks for all your responses chaps

Well, to cut a long story short, we went back to the vendors to re-negotiate the price considering that the house required a lot of work including the DPC etc, just to knock 10k off the price but turns out they aren’t interested in any price reduction. So l have pulled out of the purchase - from what l gather they are only interested in someone agreeing to buy the property without performing a proper survey - oh well - will start looking again for a property

Cheers guy really appreciated your help on this
 
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