Damp or poor ventilation??

[Hazel85]

Hello

We have recently moved into our first house. It is a Victorian brick built house built around 1880. The house has had new PVC windows put in and has 4 previous treatments of rising damp, in 1976 a chemical damp proof course was inserted, again in 1985 and in1987 there was also some work dine in 2004 but without plastering.

When we moved in the walls were wet! There was no mould and the skirting boards were dry. After a few days of opening windows and having the dehumidifier on the walls began to dry out. The damp is on the walls in patches in some places but shows the tide mark in others. Also the damp is on both sides of the house on the walls that are shred with next door. (It is a terraced property) After a week the wall were dry to touch, the actually got remarkably better after one day. However 2 days after a heavy rainfall and on humid weather the walls were wet to touch again. The worst bit is under the stairs and on the wall by the stairs, this never seems to fully dry out. We haven't had any wet weather recently and the walls seem dry again. What is also strange is that the house does not smell damp either!

Although the walls dry out and the get damp, the paint is peeling off and the plaster is damp behind the radiator under the stairs. The gutters outside seem ok and there isn't a problem upstairs. What is also baffling is that this damp comes up about 1 m high, even about 1.5m in some places.

Can it be anything to do with the plaster? I know that older buildings need to breathe!

I would be grateful of any help,

Thanks, Hazel

 

[MdB]

Hi Hazel,

What is the outside ground levels like compared to inside? This is the most common problem so worth mentioning. Also are the damp walls internal walls, external walls or both?

You may also want to read the damp FAQ here: http://www.periodproperty.co.uk/forum/viewtopic.php?f=6&t=6777

 

[88v8]

Arrrgh, poor you.

If the skirtings are old but not rotting, then it sounds as if the moisture originates in the house rather than in the walls.

Plastic windows won't help as they seal up a house which was not designed to be sealed.
There would also have been a number of open flues to assist ventilation - do you have any working fireplaces?

Do you, or did the previous owners, have a tumble drier, or hang wet clothes in the house?
Is there a shower with no extract fan?
Is there are an extract fan in the kitchen?

Lift a couple of floor boards downstairs in each room, and look/feel at the ground beneath, It should be dry cement. Note whether the floor nails are rusty.
There should be a good draught under the floor - if not, look for blocked air vents/bricks front & back.
Leave the boards loose, and next time there is damp in the house look underneath again.

What are the walls plastered with? Is it actually plaster, or cement render?

Hmmmm..

Ivor

 

[AMc]

Have a read of the Damp FAQ which is cunningly hidden...
http://www.periodproperty.co.uk/forum/viewtopic.php?f=6&t=6777

If there are trickle vents on the windows make sure they are open and not blocked.
Depending on what has been done to seal the house up you may need to do some work to let the structure breath and/or improve the ventilation on a permanent basis.

 

[Penners]

http://www.youtube.com/watch?v=Ei7wYtj5vYQ

There's some excellent advice above. To develop it a little further, I could perhaps add that you're going to need to approach this problem on a step-by-step basis. Damp has many possible causes, and the only effective way to discover which one(s) you have is to try one solution at a time, then wait to see whether it has worked.

As others have said, I think my first approach would be to try and eliminate condensation as much as possible. Try to minimise its creation inside the house, by tackling things like steamy showers, drying wet washing on radiators... that sort of thing. Do as much as you can to keep damp air away from the damp walls.

Warmth and ventilation are the solution to such condensation as still exists. Let the warm air soak up the moisture and then let ventilation carry it out of the house.

I have to say that I don't necessarily agree with 88v8's assertion than there should be dry concrete under your floorboards. Provided the house has not been excessively modified since Victorian times, then it's more likely that the downstairs floorboards will rest on wooden joists, underneath which will be an air gap, then soil. If this is the case, then check that the air gap is well ventilated by air bricks in the outside walls, and make sure those air bricks are clear of any blockages.

But if your downstairs floors are concrete, rather than timber, then it's possible that this may be a contributory factor to rising damp in the walls. The subsoil moisture, unable to escape through the concrete, can migrate sideways and get wicked up the walls.

MdB's point about outside ground levels is also highly relevant.

However, first things first - try the warmth and ventilation advice for a while and see whether you manage to improve the damp. Then we can all discuss the next stage, if it proves necessary.

 

[Hazel85]

Thank you all for your help.

Im going to try an aswer as many of your questions as possible.

We dont have an extracter fan at the moment in the kitchen and there isnt one in the bathroom either! I have just been opening the window.

Also or double glazed windows don't have trickle vents, they have a double latch on the, so i have been locking them on the second latch to allow some air in. We have a coal burner in the first fire place which is in working order, so i have had the door open on it as the chinmey has been blocked around the flue leading to it. Our other chinmey downstairs is blocked. Some moderation has been done to that and i think it is completely blocked off.

Our ground levels outside the front of the house are slightly higher inside, there is concerete by the front door and there was a flower bed by the external wall which i have cleared. I have also lowered the soil a bit so that it is almost as low as the bottom of the air brick. The air brick was blocked up with snail shells and soil etc which i have now cleared. There also seems to only be one air brick at the front of the building too. However this external wall inside of the house doesn't have the problem. Our air brick on the other side of the house is effectively blocked off because the extension for the house is built at this end.

Im not sure what the walls are plastered in. I know that there was work done to the house in 2001 because the middle partition wall had been knocked through and needed structural work . Our front room and dining room are now one. Also the damp work that was done in 2004 was plastered by someone else so im not sure about that either. I have a funny feeling it is modern non breathable plaster.

Also i have written to the previous owners but have not recieved a reply. Im not sure where they have been drying thier washing but i know they didnt have a tumble dryer. We have been drying our washing outside.

Thank you again for your advice and info. It has been helpful.

 

[Penners]

Hazel - I'm sorry to be pessimistic, but it sounds to me as though you have an extensive collection of damp-creating situations, there! No ventilation (particularly important in the kitchen and bathroom), no window vents, no open chimneys, block air-bricks, high external soil levels...!

For what it's worth, I suggest that the very first thing you should do is install extractor fans in the bathroom (priority 1) and kitchen (ditto 2). If you can't immediately lower soil/concrete levels below the interior floor levels, at least get those air bricks cleared. If they're lower than soil level, then construct little "wells" so that the air can get to them - but put little roofs over the wells so they don't fill with rain.

 

[Hazel85]

Yes I think so too.

Thanks for your advice!

 

[worms]

I wonder also what sort of heating system you have? You mention damp behind one of the radiators.

It is possible that once the heating is on for the winter (ours is already on, we had the first frost a couple of weeks ago!) the damp situation will be improved. If you have either a gas or oil boiler in the house, it will suck huge quantities of air through the house and out the flue, which I believe helps.

 

[Penners]

the heating is on for the winter (ours is already on, we had the first frost a couple of weeks ago!)

Heating, worms?!

Doesn't that melt the igloo?

 

[worms]

Doesn't that melt the igloo?

Now that would be an interesting question for the damp FAQs!

Big skenes of geese passing over this morning heading south!

 

[Penners]

I think you've been spending too much time near Aberdeen!

Down here in the balmy south we call them 'skeins'.

P. Edant

 

[worms]

I think you've been spending too much time near Aberdeen!

Down here in the balmy south we call them 'skeins'.

P. Edant

You know, I thought it didn't look right!

I'm glad you went for the geographical rather than the anatomical reference!

 

[88v8]

I have to say that I don't necessarily agree with 88v8's assertion than there should be dry concrete under your floorboards.

Sorry, that was a wooly comment of mine. What I meant, there will be joists, sitting on sleeper walls, and an air gap which might be 9-18" depending, but the ground beneath should be covered in weak-mix concrete known as the 'oversite' which was used to keep the underfloor from being overly damp. This does not usually contain a dpm. Now, I don't know when oversite begain to be used, as opposed to just leaving the bare earth beneath, but whether you have oversite or whether you have bare earth as Penners says, it should be dry.

I would have said there should be at least three air bricks front and back. Perhaps one under the front step? and two under the front rooms, and three in the back. A rear extension is no excuse for having no rear airbricks, if the extension floor is solid them the air bricks should have been piped within the concrete as was done when our conservatory was built.
Bodgers lodge to just block them off. Without good airflow there is a serious risk that the floor will rot. When you take up a floorboard there should be a good breeze coming out, if not there will be trouble.
However if the extension floor is floating (wood on joists) then you can install air bricks in the outer wall, having first checked that the original air brick holes in the back wall are clear. Actually, although I say 'bricks', cast-iron vents are better as they have a larger opening.

Ground level.... the air brick normally sits on the damp-proof course, and that should be at least 6" above ground. So the ground level should be 6" below the bottom of the air brick , otherwise there is a high risk of rising damp. That goes for the back of the house as well.

Chimney... if it's been blocked at the bottom with no air vent, check that it is properly capped at the top to keep the rain out.

I agree with Penner that extract fans would be a logical starting point, at least they will remove the worst of the damp created by living in the house.
Shame that previous owners seem to have spent a lot of money on 'cures' without getting to the root causes.

Ivor

 

[Hazel85]

Thank you for all your help!

We decided in the end to pay for damp and timber survey. We got our report today. Thankfully there is no rotting of the floorboards or woodwork! We do need to remove the old air brick and replace it with three air bricks to the front of the house and three to the rear of the main Victorian building, plus some vents (but don't know where). We also need to get a drainage channel put in to front of the house. The quote we have been given is £1200 is this too much?

We also need to get our walls replastered downstairs, but haven't been given a quote for this yet. Does anyone know a good plaster that won't break the bank too much in essex? We are on a very tight budget as we have nit long moved in!

Thank you

Hazel

 

[Flyfisher]

Thanks for the update Hazel.

That all sounds quite encouraging to me and seems eminently sensible.

It's hard to say if £1200 is a good price for the new airbricks and vents plus a 'drainage channel' without knowing the details of the work involved, but it certainly sounds like the right thing to be doing. If your budget necessitates breaking the work into a few phases, I would put the airbricks and vents as the highest priority. It may even be possible that this alone would result in a sufficient improvement such that the drainage channel is not actually required.

As for the plastering, if you can put up with messy walls for a while, you could save some money by removing the plaster that needs replacing yourself. Fairly hard work, but not difficult, if you see what I mean. Removing the plaster and leaving the walls bare for a few months would also help the walls to dry out, though I appreciate different people have different tolerances to such disruption.

 

[88v8]

....different people have different tolerances to such disruption.

The alarming thing is how easily one becomes accustomed to living in a building site. Our first house, we had access between exchange and completion and we stripped off all the wallpaper in the house. Some of the plaster was blown and had to be redone. It was rewired, I put in heating. Every wall was messed up, every floor was lifted, the original paintwork was nut brown... What with one thing and another, only two rooms got finished in the five years we lived there, visitors were appalled that we lived in such a mess but after a while we didn't notice it....
Rather the same in our present house, although we did at least confine ourselves to working on one room at a time.. on the whole... and that only went on for 25 years...
Trying not to repeat the process in our notnew cottage, but mission creep is creeping in and now the dining room floor relaying has been joined by the sitting room floor relaying and the cellar steps rebuilding and various chimney repairs, all of which makes mess that is hard to confine in a house with no internal doors.

Hazel, I wouldn't rush to have the walls replastered before you can assess whether you have remedied the root causes of damp. If the damp is still there it will eventually emerge through the new plaster, and if you have the work done in waterproof plaster then the damp will just reappear higher up. It could take 6 months for the walls to dry out, so it would indeed be a good idea to knock off the bad plaster to speed up the process. I'd do the extract fans, airbricks, lower the ground level at the front, run the heating over winter, and see how it feels in the spring.
Not exactly how you envisaged your first year in your first house, I guess

If you've got to talking with the neighbours, you might mention that you have a 'couple of damp spots' in the house and ask if they've had any damp problems... given that it's a terrace and builders of old weren't always saints, there might be a common cause that goes back to the original design of the house.

Ivor

 

[Flyfisher]

....different people have different tolerances to such disruption.

The alarming thing is how easily one becomes accustomed to living in a building site. Our first house, we had access between exchange and completion and we stripped off all the wallpaper in the house. Some of the plaster was blown and had to be redone. It was rewired, I put in heating. Every wall was messed up, every floor was lifted, the original paintwork was nut brown... What with one thing and another, only two rooms got finished in the five years we lived there, visitors were appalled that we lived in such a mess but after a while we didn't notice it....

:lol: :lol: :lol:
That is so, so very true.

 

[Roger H]

Regarding extractor vents, I'd suggest giving some thought to a single room MHRV - mechanical heat recovery ventilation. Vent Axia etc.. do them and they pull the air out as per a normal bathroom/kitchen extractor fan, but then use the heat in the outflow to warm in-coming air. So fresh air, but less costly to heat than unregulated drafts from trickle vents.

 

[tony]

Use a core cutter and core a 4 or 6 inch hole for added ventillation.
It will cause less damage than a breaker.

Better for internal finishes etc

Fit a nice grill to keep vermin out