Cavity wall insulation and Damp ??

[utterlydiy]

Selling my parents bungalow and the buyers had a survey carried out, with some minor faults for backing out.

The so called main reason, Damp in the Bedroom, but there is no visual sign of this, everything is good, wallpaper etc. The roof and tiles etc. look good. The agents have also said this is a minor problem if it was right.

Read the surveyors report for 1991 when they purchased the property, nothing reported. No structural modifications etc. have been carried out since. As far as I can tell all the pointing on the exterior walls is ok.

"Just noticed similar other topics regarding this. The property has wooded floors (as far as I know are good with no creaks or damp) and from a recent inspection under the kitchen for another reason, everything is dry and the air bricks are clear."

If there is damp as reported by the surveyor, could this be caused by the cavity wall insulation carried out in 1991 on behalf of Cornings, acting like a sponge or similar.

If not what could cause this problem.

 

[JohnD]

more often condensation, or pipe leak.

If you describe where the damp is, what the floors are made of, if there are signs of damaged gutter outside; leaking shower adjacent, leaking radiator on wall, gaps round window, this will give some clues.

We like pictures.

 

[utterlydiy]

Thanks,

At present I don't know as the property is some 150 miles away, and my parents are deceased to ask.

I shall try and ask the agents for more info from the report, if the client will give any.

 

[archway]

Hi,
I have seen on several occasions cavity wall insulation transmit damp through to the inside of a property. More often than not where the wall in question is on the prevailing weather side of a building, so that the external brickwork gets soaked and finds its way across the cavity wall insulation to the inside. No easy solution if it is this. If you inspect fot broken/ blocked gutters, leaking pies and can find no clues, you will have to remove a few outside bricks and look in the cavity. It will be made worse if there are snots on the wall ties, and often they do not slope slightly towards the outside. Hope this helps

 

[utterlydiy]

Thanks,

The Bedroom in question does face the weather so it could be as suggested, travelling in some way.

Would it be of any benefit of painting the outside wall with a clear waterproof finish of some sort.

If so what would be the best suited.

Suggestions please.???

thanks

 

[^woody^]

You can't assume anything regarding the supposed dampness without sight of the survey report.

There are many possible causes and type of dampness, and without more detail, then discussion is a bit pointless.

If I give you an example from a recent survey ... dampness in a bedroom was caused by a lack of an extract fan in the kitchen.

 

[archway]

I have never come across any of the supposed silicone sealers that you paint on doing any good. As to woody's comment about the survey this can be true but very often where the cause of a probelm is not obvious they will say something alsong the lines of "further more detailed investigation is required which may require some parts of the building fabric to be removed to ascertain the extent and cause of the problem". I think if you do not know much about building works, you need to see a surveyor on site to get his thoughts on how to proceed. I would remind you that very often a broken or leaking gutter can cause all sorts of damp problems. Check your basics first.

 

[utterlydiy]

The agent has tried without any luck to get hold of a copy of the Clients surveyors report.

We are not at this stage required to purchase a HIP (Home Information Pack), till January 2008 as the property is currently on the market before 1st June.

The agent has suggested that we have a surveyor to carryout a survey to outline any faults for our benefit, which then can be handed to any new clients interested in purchasing the property.

Yes or No ???

 

[toptec]

Hi Guys

I have just bought a 1960's bugalow in need of modernisation. Following the survey we found that there were various parts of the building suffering from damp.

Having spoken with my surveyor one or two of the damp points are due to broken guttering and poorly fitting porch panels but his view is that most of the damp is caused by the life style of the occupants. In my case the house was occupied by an elderly couple. He has recomended a prolonged airing of the bungalow and adjustment to the air circulation. Most of the windows had been painted shut and on inspection we could feel the moist air.

It is worth offering to buy the survey report for your parents house off the buyers, reduced price of course, as it is of no use to them.

toptec.

 

[utterlydiy]

Back again.

As we could not get a copy of the peoples surveyors report. We had our own carried out and its not good.

1) As the house was built in the 70's they used a bitumen based DPC and from the readings around the skirting boards all round the perimeter walls, theres a damp problem in some areas in the 'Red' 40%. This also applies to the inner walls but at a far lower reading. Over the years the dpc is breaking down being pushed out and maybe punctured, where as today a plastic based DPC is used and is far more durable.

2) As my parents had Cavity wall insulation carried out and this appears to be expanded foam. But the walls were good apart a few areas of damp which is suggested there being a Wall tie at that point being bridged to carry the damp from the outer wall to the inner.

As far as a remedy but not a cure, this is going to be costly to carry-out.

Injecting a new DPC by a chemical compound, but this means stripping the inner walls from plaster etc up to a meter high from the skirting boards and renewing the skirting boards also. As far as the walls go, its recommended to dry-line the walls all round the perimeter inner walls with more insulation on top of a DPM, but with an air gap between the insulation and the plaster board.

Otherwise it could be a major job to carry out a cure by removing the insulation installed, because its expanded foam (not rockwool or expanded polystyrene beads) to clear the cavity to stop the bridging. Meaning several area's of the outer brickwork would be needed to be removed to gain access and re-bricked.

The costs estimated in the 3k to 4k to carry this out.

Comments please

On a separate Topic when you see the fitting of polystyrene boards into the rafters of a roof on these DIY shows, you see no air gap between the board and the felt. Surely this is a starting point of damp and then rotting of the rafters. ??

 

[terrysayers]

my wife is an estate agent and has seen this happen on so many occasions. we are selfs have had problems with damp. i suggest you offer to reduce the agreed price to half the cost of the work and let the purchaser do the rest if you get the work done it could spiral and cost even more and waste time in the process.

then there is the situation if they pull out while the work is in process.

HIPS has been delayed for even longer now and it will only be on 4 bed houses to start with

just something to chew on

 

[jonny_throstle]

I think this is right but i'm sure someone will correct me if i'm wrong........
Damp meters work by detecting electrical resistance in materials (between the 2 probes). Because water is a good conductor of electricity it is assumed that a high reading means water (damp) is present. This is not neccessarily the case though as other things can cause low resistance in building materials such as salt. Maybe this is something to bear in mind ?

 

[AndersonC]

Injecting a new DPC by a chemical compound, but this means stripping the inner walls from plaster etc up to a meter high from the skirting boards and renewing the skirting boards also.

Please don't waste your money getting a 'DPC' injected. If the problem is a bridged cavity then a DPC injection won't make much difference (their effectiveness when the cavity isn't bridged is questionable anyway)

On a separate Topic when you see the fitting of polystyrene boards into the rafters of a roof on these DIY shows, you see no air gap between the board and the felt. Surely this is a starting point of damp and then rotting of the rafters. ??

There should be a 2" gap between the insulation and the inside of the roof covering (sarking/slates etc) to allow the timbers to be ventilated.

Damp wouldn't be as much of a problem if there was something called fresh air moving around buildings, cavity walls and roof spaces to ventilate them. These days we like to prevent air movement within our homes as it makes our houses cold (and Environmental types complain about carbon emissions), by shoving insulation into every possible space. We're then left with resulting damp problems which attract "wonder cures" in the way of chemicals etc. Interestingly, these mostly aim to treat the symptoms and not the cause.