Hi all
I am a bit of a nube and need some advice.

We have a 1930s semi with a sub floor / suspended floor.

The house is built on soil and rubble.

We have a damp smell down stairs that makes me cough after a while. We have an internal wall and a partition wall to next doors downstairs that are reading as damp on a meter. However, the bathroom and our bedroom also smells damp.

Now we have a quote for a chemical dpc and plastering for the internal wall and party wall which is 800 quid but I keep thinking to myself why would the bathroom which is the other side of the house smell and why would our bedroom? There are no visible signs but is a strong smell and is getting worse. I've checked for leaky pipes and seen none.

One thing I have been worried about is that as most of the house seems to besmelling of damp now I thought it might be something to do with the cavity wall insulation being saturated. We are in quite an exposed spot backing onto parkland with wind driven rain onto the property.

I was thinking if the following might be a good strategy?

1. Get dpc done on internal and party wall.
2. Ensure all air bricks clear that lead to subfloor void
3. Get cavity wall insulation removed as I've read that this can be a bad idea on an old exposed house that needs to breathe. I don't know how and who?
4. Introduce some roof vents in case attic condensation is running into wall cavities.
???

To be honest I am not sure what to try. We just have a damp smelling house that's getting worse and gets on my chest a lot.


Any ideas?


Oh, forgot to mention that we had a minor water leak that looked as though it had been occurring for sometime under the house. We fixed it over a year ago though. However, from that point inwards the house has been getting worse.
One other thing. About 6 months ago our neighbours had their dpc done via injection over most of their side.


Any thoughts or ideas?
Cheers
N

The place to start is the roof.
Get a ladder and or a pair of binoculars and standing across the road, look at each slate or tile to check its in place and not broken, missing or cracked.

Look at the chimney, check its not bent, there is no missing cement round the pots and that the render is not cracked or missing, check the flashing round the chimney, is it in place and doing its job.

Check the gutters and the down pipes, are the gutters clean, does the water run/pour over the sides when it rains hard, are the down pipes, cracked are the joints leaking.

Get up in the loft with a bright light and look at every piece of wood that makes up the roof, check to see if there is any sign of damp, mould, white stains, water marks, wet or dry rot. When you are sure the roof is perfect move on.

Walk round the house, look at the render, is it cracked, is any of it missing, if the bricks are on show is the pointing in good condition.

Do the windows and doors fit properly, is the rain getting in round the frames.

Look just below the front and back door frames, can you see the damp proof course, is any part of the garden touching the wall above the damp proof course.

All surfaces outside the home should be more than six inches below the damp proof course to stop the rain from bouncing off the ground and making the wall wet.

If all that lot is OK and in good condition, check all your water pipes, the bath, handbasin, kitchen sink, toilet etc to see if you have any leaks.

If everything is still OK, consider your way of life.

Do you have central heating, do you turn it off or down at any time.
Do you have extractor fans in the kitchen and bathroom, do you use them.
Do you keep the kitchen and bathroom doors closed at all times.
Do you keep the windows closed during the winter.

Does this problem only happen in the winter, does it get better during the summer, when you have your windows open.

Have you spoken to the people next door, you have a party wall, if its damp on your side, it must be damp on their side, ask if you may look at their wall, where the damp corresponds to your side. Is the lady of the house keen on indoor plants, is she over watering then.

Do you have any indoor plants.

Do you have any dogs.

Rising damp lifts itself through the mortar between the bricks to a height of four feet above the ground outside and/or inside, then it is overcome by gravity and stops.

Cavity wall insulation was banned for years in the west of the country and on exposed high ground as the wind blown rain, pours through the walls making the insulation wet and transferring the water to the inner walls.

Water is a 4,000 times better conductor of heat than dry air, a wet damp home is expensive to keep warm, dry air is a lot cheaper to heat, turning off central heating stops the warmth of the room pushing the cold damp out.

If you have a leaking roof, gutter, down pipe, water pipe, rain coming through the walls or condensation the damp can be in other places, even upstairs.

The important thing is to find out before you are conned into spending any money on unnecessary work.

So which is it?
Keep in touch, advise progress.

Hi
Thanks for your advice. I've checked the roof and don't think it is that. Windows are always open on the latch even in winter to get some air in. We have a large bathrom window that I also tend to leave open when getting a bath or shower plus an extractor kitchen fan, so think it unlikely that it is lifestyle.


I've pretty much had most of the floorboards up and all of the airbricks off around the house (10 in all) to check the cavities. I've summarised what I've found in the picture attached. Summary is that we have damp on the walls anywhere up to a couple of feet from the floor in more than one room plus behind 3 air bricks I found that the cavity wall insulation was wet and soggy.

I am starting to think that the problem may be one of the following combined with a DPC that is on its way out (combination of odd bits of slate and a kind of bitumen whioch makes up the majority):

(1) Simply Ground water (rainfall) - the base of the subfloor is about 2.5ft below the outside ground level and the outside ground level is about 3ft below the park level that our house backs on to. The house is built on clay soil and the park and garden do tend to get soggy after heavy rainfall.

or

(2) We have a broken pipe or drain somewhere that is putting water into the ground under the house.

or

(3) Water that hasn't evapourated or soaked away after discovering that the soil stack had been leaking under the subfloor - I have a suspicion probably for years - and worse when had a spate of drain blockages at the end of the driveway. All of this was sorted about 12 or more months ago by United Utilities who fixed their pipe on the roadside and we moved our soil stack to the side of the house from the back of the house (it used to be boxed in within the house!).



I'm really not sure which it is and am a little loathe to remove the fitted kitchen and stuck on floor tiles to check the water mains pipes.


One of my mates is a builder and he was saying that provided the sub floor is vented well it shouldn't matter that I have wet soil as long I have a good DPC! Is this always the case or anytime the case?

He said that when it rains heavy the subfloor under his house gets 2" of water. He said that he has even had frogs under there. What he did was when he bought the house was to put in a DPC a few bricks below the joists (below floorboard level) and a DPC at skirting board level.

I just worry that if it shouldnt be damp under the floor then it shouldn't be damp!


Any thoughts on any of the above and how much a DPC might cost (i.e. one under the floor boards and one at skirting level incl. plastering to 1m high?


Help greatly appreciated as this musty smell is getting worse plus am convinced it is giving me a sore nose and throat!

Thanks

N

-- Sun Jun 20, 2010 10:27 pm --

Pic here

but I saw one of those daytime TV shows during the last week or so...1930's house..sounds similar construction to yours..
within a couple of years of having cavity wall insulation put in...rising damp and or dry rot... everywhere..the 'Beads' of the insulation had blocked up the air bricks..and compromised the dpc.
.suggest lifting carpets at the edges of the room and looking for any signs of damp/mould there..

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Hi
I forgot to add the patio doors onto the kitchen. They cover the whole of the outside wall of the kitchen. Probably irrelevant!
Ta
N

-- Sun Jun 20, 2010 10:46 pm --

Thanks Wine-o.
Our's is white fluffy stuff. Soggy in the places indicated at ground level but dry further up. All the air bricks are clear from rubble and there are brushes to keep out the fluffy stuff inside the cavity wall. All checked an clear. THing is I think this cavity wall stuff is a nonsense for old houses. Old houses were designed so they can breathe through the cavities so putting stuff in there is surely going to affect the air flow. Even the air vents at the top of the cavity walls are sealed up with silicone to stop water getting in and making it soggy.

I think I might get it removed if this is possible. Some kind of hoover?

Thoughts?
Ta

-- Mon Jun 21, 2010 12:51 am --

Hi guys (and gals)...


I've attached photos that relate to items (1) and (2) in the diagram.

(1) Damp boards towards edges - it looks like varnish - maybe it is - but either way its damp when I use the damp meter there where as on the non dark bits I dont get a damp reading. What's going on?


(2) The old bay window foundation which is in an extension (if you call it that as its only an extra 1.5 or so metres) of the house. Its damp all around the base of it and either side (not shown in the photo).


Could it be simply the drying out left over from the incident 12months ago?


Thanks
N

-- Mon Jun 21, 2010 12:53 am --

Ano pic

-- Mon Jun 21, 2010 12:53 am --

ano

-- Mon Jun 21, 2010 12:54 am --

ano

Its good the roof is OK
Having the windows open does allow the humidity to escape,OK
Presumably the window frames are in good condition and they are sealed to the walls to stop rain getting in?

You write that the damp is, "up to a couple of feet from the floor."

I am not sure what you mean when you write

."the outside ground level is about 3ft below the park level that our house backs on to.

Are you saying the damp proof course is 3 feet above the ground?

The important thing is how high is the dpc above the ground = rain bounce = wet wall above the dpc.

And more important, how high is the top of the damp above the outside ground level?

As I wrote earlier, damp rises through the mortar in the walls to a height of 4 feet, above the outside/inside damp/wet highest ground level.

If the walls are damp to the 4 foot level, then that is a good indicator that the dpc is damaged, or that the ground outside is too high, in relation to the dpc.

Damp rises through a wall via the small holes that are entrained in the mortar when mixing, the capillary/wicking effect enables the damp to rise to the point where gravity stops it. However, if you enclose damp, so that it cannot evaporate into the air, then it can rise higher.

If the walls are damp above 4 feet from the ground (not the floor), then the water is coming from higher up = probably, the rain is coming through the walls.

The rain coming through the outside wall, running down the inside of the cavity, and as it does making the cavity insulation wet, that in turn makes the inside wall wet.
You can also have a situation, where the water runs across the wall ties, making damp patches on the inner wall.

When a dpc is working properly, and the ground outside and inside is low enough to avoid rain bounce, and when there is no infiltration of rain from the outside wall, and when the roof, window and door frames, gutters and water pipes are all OK = then it does not matter how wet the ground is, or if there is a lake under and round the home, the working dpc, keeps that water out.

If the dpc is broken, then inserting a chemical dpc is easy!
Anyone can drill holes downwards between the bricks and fill the holes with dp cream.

It is better that you do this yourself, doing it yourself will mean it is done carefully and properly.

If you hire someone to do it, they will not have confidence in their work and will want to avoid call backs and will insist that the plaster has to be removed up to four feet above ground level, then they will render the wall with waterproof cement to hide the damp. They will also drill the holes higher up the wall, result, the bricks at floor level remain wet.

If you have an SDS hammer drill, or buy on for the job, go round the inner wall drilling holes downwards between the bricks and horizontally at the vertical joins you will have a working dpc at floor level.

If you look on e-bay you will find dpc cream is a reasonable price.

The floor boards are wet, because either, the ends of the joists are wet, because of the way the joists were fitted in the walls - this is not allowed, under current Building Regs. or the walls have been plastered down and touch the floor boards.

I see that you do not show the chimney as damp? This is unusual as chimneys are hard to damp proof, because of the way they are usually used as a rubbish dump, for odd bits of brick and mortar.

As I wrote earlier, soil/ground in the crawl space is of no importance.

High damp reading on an inner wall is usually connected with a leak in the loft or upstairs, or someone over watering house plants.

Damp near down pipes, usually means a leaking pipe or gutter. Have you checked these pipes and gutters when its raining hard? (I know we have not had much rain this spring, its the driest since 1964)

The fitting of cavity wall insulation in homes in the west of the UK and those high up and exposed in the middle has been banned for some 20 years or more. (Never the less companies still sell it and people fit it.)

The idea of cavity walls, was to stop the wind blown rain from coming through the walls, cavities were vented at the top and bottom in the early days, and the wind blew round inside and helped keep them dry.

However, this also made the walls act like a refrigerator and these homes are impossible to keep warm and cost a fortune in heating = as they are in effect, merely a single skin wall. Very bad, cheap design.

The remaining walls left by the old bay window, are below the dpc and will remain damp for the life of the home.

I see that you have 8mm central heating, and that the insulation is missing in places and is in poor condition, and of course doesn't fit. These gaps represent a decent heat loss.

Looking at the last pics I would say one of the pipes is leaking, or a radiator valve and it's running down.

Whatever it definitely looks like surface water.

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Thanks Scruff. Was my though initially but none are leaking as far as I can tell around that area. Also, its a closed system and the water pressure hasn't moved in years, so if there were a leak (especially one to create thatmuch wet) I'd have seen the drop in pressure. All radiators are bled fully.

???
Ta

-- Tue Jun 22, 2010 10:55 pm --

Thanks Perry. Very grateful.

Windows and doors always open. I have a humidity meter and it is never over 35% and mostly around 25%.

Window frames UPVC, sealant ok and no obvious issues.

The base of the sub floor void is below the level of the garden. The main floor downstairs is above the level of the garden however. I think I was trying to say that as the garden is slightly below the park land level and that the base of the sub floor is below the garden level it becomes a lowest point in comparison and thus likely to see some water?

The damp proof course on the outside of the house is about 6" above the concrete outside. There is a shingle bed around the back of the house to reduce splash too.

Damp on one of the inside walls is to about 2 to 3 feet (above the skirting level) and is above the outside ground level. HJowever, this is an internal party wall and similar on an internal partition wall. I.e. no external wall involved. As per diagram really.

Gutters all relatively new having replaced the old metal ones. All the damp is around the ground level. No major issues upstairs that I've noticed. Just a strong, very strong, musty smell downstairs in all rooms now and getting slowly worse.

Sorry, chimney breast is damp in the back room (main room). Plaster is a mess up to about 18" from skirting. My fault - i missed to put it in the pic.

Loft is boarded, was up there last week and is bone dry so cannot be contributing to damp on the inner walls.


Looks like I need to get the cavity wall insulation removed, get the drains inspected (camera job I guess), and install a new DPC inside and outside. Sounds also like I need to do this mostly myself to get it done right.?

Just worrying that there is a water source somewhere that has really exposed the DPC issues.

Thanks

N