Damp walls issue

[BMac]

Got a problem. I noticed damp in a corner of my bedroom. When I moved wardrobes etc I discovered a triangle of damp from near the ceiling to the floor in one corner and it extends about 15' along the (external) wall to a height of about 3'.

Background - old cottage style bungalow built 1922, solid walls, damp-proofed 16 years ago when I moved in. I got all the solid walls at the front half of the house treated with damp-proof course (injection) and there is no damp anywhere else.

At the minute the damp is visible and the paint and plaster is 'foaming' and falling off in places.

I am gutted but that won't fix anything. Is is worth getting a dehumidifier to dry the room out before calling a builder, who will probably find thousands of pounds worth of work to do, just in case it's an air circulation problem? The damp is only behind units that were along the exterior wall.

Any advice, thoughts or suggestions will be greatly appreciated.

Brendan

 

[Oryxdesign]

Have you checked that you don't have a leaky gutter?

 

[BMac]

This is quite a coincidence. About 3 minutes ago I was outside looking for any damage that might have occurred and I wondered if the gutters were full because I haven't cleaned them for two years due to health issues and never got around to getting someone else to do them. Tomorrow I'll get up and have a look.

Thank you.

Brendan

 

[MikeG.]

Difficult to comment without a site visit, I'm afraid....so general terms only.

Firstly, if the damp-patch is behind a cupboard it could simply be that you have a cold, uninsulated wall which attracts a bit of condensation and, because of the cupboard, there is no ventilation. Ventilation is a key to avoiding damp problems. Condensation is so often the cause of damp problems, and the answers are insulation and ventilation.

Secondly, check for all possible sources of damp.......leaking gutters and downpipes, ground built-up too high outside, leaking pipes/ cistern overflow pipes etc. Are there any external cracks that might allow the ingress of water? Does your pointing need sorting?

Don't go for a dehumidifier, because it will remove the best clues you have to the problem. You want to solve the damp problem, not, mask it. Is there good ventilation to the room? Keep the furniture away from the area for a while, to see if ventilation solves the problem.

Don't get a stranger to look at this, unless there is no-one (architect, surveyor etc) that you know. They will simply see pound-signs.

Mike

 

[BMac]

Thanks Mike,

I am fairly confident that there are no leaks but the gutters could be a big factor because I have lots of Ash trees close to that side of the house and the gutters do get a lot of leaves.

I'll pass on the dehumidifier, that makes a lot of sense.

Ventilation is a issue because the rooms are small and we joined the front room to the back room (of the original house) to get a bedroom and connected dressing room. So there is only a door, 3' archway connecting the rooms and two top windows at the front. There's another medium sized window in the room we sleep in. We keep the windows and door open at night and try to keep the ventilation up but there are areas where through-flow of air is poor. I saw a system that is fitted in the attic and blows air back down to increase pressure inside the house and supposedly repel damp and improve air movement. I have no idea if it is any good.

Getting an expert - one of my mates is a plastering contractor so I'll get him out. He's very good.

Thanks again,

Brendan

 

[MikeG.]

Brendan,

the air-handling unit you speak of is called a whole house ventilation system, and because it recovers waste heat and feeds it back into the house, you will find google deals with it as MVHR (mechanical ventilation with heat recovery).

They are brilliant, brilliant bits of kit. If you live in a bungalow then I would say do it straight away. Retro-fitting in a bungalow is really easy. It is more problematic in a 2 storey house because you need to get a 4" pipe to every room in the house, and dropping 2 or 3 vertical legs through the first floor rooms is never straight-forward.

This http://www.vent-axia.com/range/air-minder-plus-ultimate-heat-recovery-unit.html is the latest version of a unit that I have fitted in or specified in countless houses, and this http://www.vent-axia.com/range/sentinel-kinetic.html is the one I plan to fit in the next house I do. In a reasonably insulated house with double glazing, they will reduce the excess moisture in the air to a level that you will very rarely see any condensation at all. Even in the bathroom, they'll clear the steam from a shower so quickly that you can shave without wiping the mirror within a couple of minutes of getting out of the shower. If you are so minded, you can watch the condensate run out of the condensate drain within a few minutes of finishing the shower or bath.

Depending on your pipe runs, and if you do it yourself (its a simple job), you should be able to do a house for £1200 to £1500........but don't quote me!!! I would never do a house without putting one in.

Mike

 

[RogerS]

Jeepers...have you seen the price :shock:

 

[BMac]

Mike,

This house is well insulated. I had the cavities done in the new section and the loft insulated during the first renovation to make the house habitable (new windows, doors, damp proofing, central heating etc). Since then I did an extension and put a new roof on the entire building. When I became medically retired I qualified for disability benefits which meant I got my house assessed and the only thing that I needed was upgraded loft insulation. That was a brilliant job, really deep and effective. So, this system you recommend is, in my opinion, well worth doing to sort out the ventilation problems in the old part of this house.

Again, many thanks,

Brendan

 

[Daven]

I am just in the process of fitting heat recovery ventilation system in our bungalow (thanks for the advice Mike). Double Glazing and floor coverings certainly have made the house damper!

The units are expensive, Screwfix do a Vent-Axia for £650 link

Not as affective as the top end but I am hoping it will still work for my requirements (2 rooms extract and 2 supply).

All I have left to do is the ducting and fitting the valves and we will be up and running!

Dave

 

[MikeG.]

Dave,

that is older generation, and therefore a bit less efficient, but will do a grand job for you. I have also fitted that exact same unit, some 14 or 15 years ago and it is still going strong. Brendan, that one may well be worth considering. As an architect I just specify things on performance, so hardly ever look at the price........and £500 worth of saving is not to be sniffed at.

Mike

 

[Daven]

Thanks Mike,

Was a difficult decision, but being made redundant a few months ago I have to be careful now, plus planing to move at some point I felt that the loss of heat saving (say 15-20%) between the newer units and this one was better than doing nothing!

The cost of the ducting and valves is surprising as well - looking at about £300-£400 - hopefully I will do it for around £1000, not bad when I have seen quotes for silly money!!

Brendan - As you sound in the same situation as us, I hope to get this running over the next week or two, so can let you know how it goes!

Dave

 

[BMac]

That's super Dave, I won't be doing this for a while until I get my mate to assess the situation and do any remedial work but I am definitely doing it.

Mike, I almost remember the name of the system I originally saw, it was a 'Positive Air something' that had one pump increasing pressure inside the house. Your system is what I'm going for, especially when it has that 'summer mode' because the front of this house is like a storage heater and gets really uncomfortable in summer.

Thanks guys,

Brendan

 

[RogerS]

Curious about the ongoing 'maintenance' required for these ventaxia type units. Presumably they have a condenser and that it operates in a similar fashion to the condenser in a tumble dryer? if so then how often and how easy is it to clean the condenser as is needed regularly with a dryer.

Or is that down to fluff in the dryer and so no filter needed for the ventaxia?

 

[MikeG.]

Roger,

no, there is no condenser. They are simply a fan in a box, with a plastic (usually) matrix heat-exchanger. This is simply layer upon layer of specially shaped plastic leaves, which allows the warm air to give up its heat to the cold air without actually coming into direct contact with it. The naturally occuring condensation drains to the bottom and runs out down a pipe. Couldn't be more simple.

Maintenance is no more than an occasional wipe out of the box, and flush through of the heat exchanger (in the bath or shower). I've done mine 2 or 3 times in 10 years.

Mike

 

[RogerS]

That is elegant. I like that.

 

[dickm]

I'd echo what Mike says. We have a full MVHR system, and it just sits there in the loft happily ventilating the bungalow without any attention apart from an annual-ish cleaning of the filter. Mind you, it's been installed since 1999-2000, so may well be coming to an age where it needs attention

With outside temp of around -5C, we are using about 4kW to keep the whole house warm. Possibly having a foot of snow as insulation on the roof helps! But at least the snow stays there, unlike most of the local houses where it melts off as soon as they put their heating on.

 

[Mark Hancock]

The timing of this thread is unbelieveable. I've just encountered the same problem as Brendon and was at a loss what to do.

Is there any way I can save/flag this thread for future reference?

 

[BMac]

Mark,

There's an option, bottom left of the page 'Watch This Topic For Replies'. I selected that to keep it alive for me.

Brendan

 

[Mark Hancock]

Mark,

There's an option, bottom left of the page 'Watch This Topic For Replies'. I selected that to keep it alive for me.

Brendan

Thanks Brendan - sorry for spelling before

I've done that. I'm just thinking a bit further ahead whe I can get round to sorting the problem. Maybe I'll just print it off for now.

 

[Daven]

I will take some pictures soon and post them here if it helps - just not been able to do much this week!

Dave