Damp Proofing

JustBen

JustBen

JustBen

Soldato
Joined
14 May 2007
Posts
2,822
Location
Cumbria
Hello Guys,

I have recently moved into a house that has some damp in the main reception room. Mostly at either end in the corners on one wall.
I had someone come and look who advised where the damp was and he said he was going to tank the walls with some black liquid which will form the damp proofing
he was planning on going 1 meter up right down the wall.

I feel its something with a little help i could likely to myself which should save me a good chunk of money.

my partners dad has used a chemical mixture from soverign chemicals which he applied with a paint brush before and said this worked well for him.

I've looked online and there's a few choices on what to use. first choice is to use plastic membrane or go down the liquid slurry type mixes.
Has anyone used the membrane? Is it as good as it makes out and do you have to go from floor to ceiling or just the 1meter up you tend to go with normal tanking?

With the slurry mixes is one better than the other? any recommendations?

Going to take the carpet up tonight and move it to a spare room as it'll be a nightmare keeping clean. Then mark out the wall for bringing the plaster off.

I'm in a good position that i am not living in the house and have a deadline of middle of september to get in so can take m time doing it :)
 
Honestly it doesn't sound like they know why there is damp.

It is possible to hide the source of the damp but what damage will that be doing to the building structure in the meantime.

Is this caused by a cold house and condensation surface damp, wipe off no issue?
Is it caused by wet walls from a leaking pipe, gutter, damaged flashing?
Is it caused by the damp proof course being damaged or having wet soil above it?

You need to understand the source and remove it before you can do anything would be my advice.
 
As Placid said, the cause is the bigger issue here and you do have time, although given it is summer it will be more likely to rear it's head once you're in.

Damp can have many causes, both houses I have owned have had it to some extent, the first was due to lack of airflow (trickle vents and keeping windows open when home really helped) and/or lack of insulation. I also had an issue in one room where the level of the ground outside was actually higher than the damp course - taking 3" off the level resolved this so were all relatively cheap to fix.

Second house was a blocked gutter which we sorted soon after we moved in.

Given your initial paragraph about the damp being in the corners, I would say this sounds like an airflow issue. I'm not sure I would seal the walls as presumably they need to breathe - possibly doing this could cause more issues but I'm no expert. For me, personally, I would look to get trickle vents and a dehumidifier.

Due to the construction of some houses, there will be an inevitable damp issue at times but using a dehumidifier can really help. I'd recommend the 'EcoAir DD122FW-MK5' from Amazon.
 
Last edited:
can only echo whats above,

i found a better way of sorting damp was to call in for a damp survey (by someone who does only the surveys) he actually looked into what was causing the damp and told us to fix that rather than rip of plaster and chemical.

our inlaws have had 2 surveys by people who do work and they both suggested this rather than trying to find the cause of the damp (independant guy came in a found the source straight away)
 
joelk2 said:
can only echo whats above,

i found a better way of sorting damp was to call in for a damp survey (by someone who does only the surveys) he actually looked into what was causing the damp and told us to fix that rather than rip of plaster and chemical.

our inlaws have had 2 surveys by people who do work and they both suggested this rather than trying to find the cause of the damp (independant guy came in a found the source straight away)
Click to expand...

How much did the surveyor cost?

We're looking at dealing with rising damp affecting a central wall, and are weighing up a cover-up job or a longer term fix.
 
Do you have a damp proof course on your outside wall - If so do as said above and make sure soil levels are at least two bricks below - Make sure gutters are not leaking anywhere.

At my old house the new neighbour next door took the gutters off his porch roof ready for some alterations - he got side tracked then came round to me and asked if I had ever had water in lounge- Neither me or next door had - In end he lifted his floor and put damp membrane down then concreted -

When I went round and looked it seemed the water had come off porch roof - splashed up wall and worked it's way inside - Reason was we had probably first damp coursing when it was invented and they built a solid wall up to damp - tipped tar on top of wall then built the cavity wall on top- He did all that work for nothing.

So check everything first
 
cheers guys,
when the 2nd company came around to give me their opinion i was there so could see what they did to come to their conclusion. they had a damp meter which they just pressed against the wall in various places. The bit in the corner is next to a door which read quite high on the damp meter. then it tailed off into the middle of the room which a reading of around 10 which they said is fine then it went up into the 20s near the front of the house. their thought was to knock the walls back where the damp was registered and then do the bit between the two main damp spots.

Prior to getting the house a 'damp report' was done which was fairly vague much to my displeasure which said a new damp proof course is required but that was it.

One of the gutters is leaking at the front of the house but in an opposite corner(getting this fixed tomorrow) and i know the chimney stack is leaking but that's on the inner walls only causing 2 bedroom walls to become damp not the ones affected downstairs (this is also being resolved tomorrow)

The house is quite warm and seems to be well insulated, we looked around this house around February so when it was colder and it was warm in the house despite the heating being off and no one living in it.

I forgot to mention and i'm not sure its relevant but the house was all pebble dashed in the last 2 years. I have checked and the air brick at the front of the house looks to be ok, its not clogged up.

The damp appears to be only near the floor.

Trickle vents i'll look into as the house is quite warm.

*edit - exact wording of report*
' high reading of damp to all walls within the main reception only. these are now require treating by installing a new damp proof course
all skirting boards on damp affected walls to be treated need replacing. all timbers that could be inspected were found to be adequate and clear of rot and infectation at time of inspection.
additional airbricks are also required to the front elevation after cavities have been cleared'
 
Last edited:
We had damp in both receptions rooms about 15 years back. While we did the house up we got this machine from HSS and the builder injected some type of fluid into the walls at regular spacing. Never had an issue again.
 
i'll grab some air bricks tonight from screwfix if they have them and fit them on Friday, reading online you should have them every 6' i have one on the front of the house and haven't noticed one on the back. Fitting the air brick would also give me opertunity to try checking the cavity wall for rubbish.

If Something like this was the cause of the damp how would i know? Do you need to leave it x amount of days and then check with a damp meter again?
 
always4lora said:
i'll grab some air bricks tonight from screwfix if they have them and fit them on Friday, reading online you should have them every 6' i have one on the front of the house and haven't noticed one on the back. Fitting the air brick would also give me opertunity to try checking the cavity wall for rubbish.

If Something like this was the cause of the damp how would i know? Do you need to leave it x amount of days and then check with a damp meter again?
Click to expand...

It could be.
Fitting air bricks is a good idea, but if you have a cavity you will need a duct to go from the brick to the underside of the floor and above that you will need a DPC mortared in to the inner leaf with weep vents to discharge any water.

The DPC should be 150mm above finished external ground level, air bricks are usually at least 75mm above the ground. That's all for new builds so if your house is old there may have to be some adjustment, a decent builder will be able to advise, it may mean you have them lower.

You should also have a dwarf wall supporting the floor (assuming its hollow timber, not pre-cast concrete) to allow flow of air.
 
thezappa said:
It could be.
Fitting air bricks is a good idea, but if you have a cavity you will need a duct to go from the brick to the underside of the floor and above that you will need a DPC mortared in to the inner leaf with weep vents to discharge any water.

The DPC should be 150mm above finished external ground level, air bricks are usually at least 75mm above the ground. That's all for new builds so if your house is old there may have to be some adjustment, a decent builder will be able to advise, it may mean you have them lower.

You should also have a dwarf wall supporting the floor (assuming its hollow timber, not pre-cast concrete) to allow flow of air.
Click to expand...

The air bricks are really not very far of the ground. I've noticed i have two at the front and none at the back.

Can i use something like
http://www.manthorpe.co.uk/Building...Underfloor-Vents/Refurbishment-Weep-Vent.html at multiple points? Looks a bit to simple.

I've taken the skirting boards of tonight. some of the wall is rather damp!
 
Ordered 4 trickle vents for the window and french doors. going to drill into the wall where the wallpaper was damp t see if it is actually wet.
 
I have solid stone walls and had crumbly plaster on my front wall and a little damp.

I had the walls stripped back, injected and internally re-rendered with additive and plastered. Personally, I think the re-rendering did the job, rather than the injections, but at least it's all done now and it's been fine for a few years.

Mine's an old house and I suspect the wrong render/plaster had been added at some point, causing the issue.
 
Well i spent all yesterday around the house...
First i took the plaster off around the skirtings to make a nice clean cut as it was crumbly after taking the old skirtings off. The plaster was dry
I then took the wall paper off and there was some black dots behind a couple of bits, the wall was a little wet on the surface but the wall paper was quite thick so suspect not breathable.
I drilled a few holes into the plaster where the damp was 'detected' and it was dry
So i'm happy i spent a few hours reading the link joelk2 provided as it's saved me a chunk of money. How the firms quote over a thousand when there's nothing wrong is beyond me.

oh and in preparation to making a mess bringing the carpet up i realized there's a very nice wooden floor which ive decided im keeping. The carpet from the room is going to be enough to carpet the two rooms upstairs that need new ones.
 
Last edited:
glad it was of some use.

when we had areas of damp (on the building survey) the damp survey guy said most of our damp would have been caused by our wallpaper (thick wallpaper on every wall in the house)

we stripped everything (some room were wallpapered ceilings)
 
joelk2 said:
glad it was of some use.

when we had areas of damp (on the building survey) the damp survey guy said most of our damp would have been caused by our wallpaper (thick wallpaper on every wall in the house)

we stripped everything (some room were wallpapered ceilings)
Click to expand...

I think this was the cause for the mildue, reading up you can buy nonwoven wallpaper which is breathable so you wont' get mildue . Also looking into clay based paints from earthborne as they're breathable as well.

The money saved should mean i can afford an induction hobbed oven :)
 
always4lora said:
Ordered 4 trickle vents for the window and french doors. going to drill into the wall where the wallpaper was damp t see if it is actually wet.
Click to expand...

Well that's a waste of money, trickle vents literally only exist due to stupid legislation.

You can easily maintain airflow in your house by opening your windows when necessary.
 
You must log in or register to reply here.
Back
Top Bottom