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Damp Proofing Questions

Our expert damp proofers have kindly agreed to share their wisdom on such topics as removing mould patches, rotten timber, causes of mildew, damp basements, rising damp, floor construction, flooding and waterproofing and much more.

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829 Questions: Damp Proofing


Builder cut through DPM

I have had a two storey extension built. There was a misunderstanding with one of the young lads on the site, who cut through the damp proof membrane with a stanley knife - to 'make it look neat'. There is now a gap left, where the dpm is cut off level with the floor base, and the dpc. Because the house is quite low down, the exposed brick became wet when it rained over the weekend. As a fix he painted the exposed course of bricks with Wickes damp proof course. When it rained, this became wet, and obviously wasnt up to it. To further repair, he has now glued membrane to the top layer dpm, and glued this to the wall, bridging the dpc. My question is, beacuse this is glued to the top dpm, can moisture now go in between the two dpms, i.e. into the insulation layer? If so what would be the result? I am thinking of re exposing the trimmed off lower layer of dpm myself (I've lost trust with his workmanship), and gluing a new strip to it to extend it up against the wall above dpc layer, and fix it against the wall with plaster. Any advice? Does that sound like a good course of action to take? Also - should i re trim the top dpm back to the height of the slab so that air can get down into the insulation layer?

Ymr_anonymous_xyz 13th Mar, 2013 Damp Proofing
1 Answer u1

What order to do things in? Damp before Electrics?


We have just bought a Victorian terrace in need of some work. It requires a full rewire but it also has damp.

We have a small amount of rising damp, but a basement that we have been recommended to have tanked with SIKA. In addition to this part of our kitchen wall is below ground level and recommendations have been to treat up to 1.9m with waterproofing (although not SIKA).

We need to do the damp quickly (to claim back a mortgage retention) but have no idea whether to do this first or get the electrics done as not sure which is more invasive. Concerned that if any parts of walls need to be removed for the rewire that it would cancel our damp guarantees.

Any advice very much appreciated.

Yevamay78 13th Mar, 2013 Damp Proofing
1 Answer u1

im getting damp patches on my outside wall just above skirting boards

im in a end terreced house and upstairs in my bedroom im getting damp patches just above my skirting boards???

Yfliss_80 6th Mar, 2013 Damp Proofing
1 Answer u1

Outside yard higher level than house?

I'm purchasing a house, and the survey has recommended the outside yard (which is concrete) be lowered, as it is now slightly higher than the utility extension [outhouse-style construction] and is causing some rising damp to the utility and adjoining dining room.

How would one go about this, and is it a big job - would extensive damp coursing be required, and would there be damp still in the floor for some time, as I'm assuming even after lowering the level, the structure that is damp will need to dry out? Thank you.

Yfirsttimebuyer22 6th Mar, 2013 Damp Proofing
1 Answer u1

passyfier vents

can one fit a passyfier vent in a timber framed building?

Ytonyraymond 26th Feb, 2013 Damp Proofing
1 Answer u1

Damp area on wall

We recently moved into a 1920's property which we have started renovating. After stripping off the wall paper back to plaster in one bedroom and have noticed that on the outside wall, there are 2 patches where the plaster feels almost soft to touch/springy and slightly damp/moist. One area is around the top of the wall before ceiling level and the other is about half way down the wall.
The other 3 walls have been re plastered but have held off with this wall as we are reinstating the fireplace but want this possible issue resolving to avoid any hold ups when the builders arrive to work on fireplace.
Any advise would be greatly appreciated.

Ybecky_ward 25th Feb, 2013 Damp Proofing
1 Answer u1

flood water above damp course

We have an injected damp course in our 1800's red brick/rendered house. Our house flooded in the recent bad weather, we had one foot of water inside the property and between two and four feet of water outside the property. Does the damp course need to be replaced.

Yelle_11 23rd Feb, 2013 Damp Proofing
1 Answer u1

What can I do about condensation on bedroom walls?

My house is 1930's. I am fairly sure we don't have cavity walls but we do have double glazing. The 2 back bedrooms have a problem on the walls with what i think is condensation. When it gets cold the walls get wet, resulting in damp, particularly in areas where furniture etc is in contact with the wall. The small back bedroom is the worst as it has 2 outside walls and is also very cold. I would like someone to take a look but not sure what I would be asking them to do as yet. Any advice would be appreciated to steer me in the right direction.

Many thanks,

Nickie Heath

Yheath 1st Feb, 2013 Damp Proofing
1 Answer u1

How to fix damp, mould, cracks and flakey plaster

We have a 1930's property and we have recently found several areas inside the property (both floors on external walls) where the walls and skirting are damp to touch. There are some areas that have mould and there is a lot of flakey and soft plaster on and around the ceilings on the upper floor rooms. We suspected the gutters may be overflowing so these have recently been cleared and we planned to get a dehumidifier. We want to replaster one of the bedrooms that is particulary bad however we want to be sure we have identified the problem. Since clearing the gutters most of the areas have improved however there is still moisture in other areas. I have also now noticed a lot of cracks around the house and I am unsure if these were here before. The cracks are generally around door and window frames but there are small cracks all over the house. I don't know if I am becoming a bit paranoid now but I would like to be sure that there is not a bigger problem before I arrange to have anywhere replastered. Should I get someone round to inspect? And if so, who do I need to contact?
Many thanks

Ynoahsark_52 21st Jan, 2013 Damp Proofing
1 Answer u1

White fluffy mould

We have a very old terrace and under the front window and side wall we have something growing on the walls. It is white and fluffy. You can wipe it away, but it keeps coming back. Any ideas? The house is near the seaside, I don't know if that is relevant?

Ythemadstans 20th Jan, 2013 Damp Proofing
1 Answer u1
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