Damp Spots on wall

[kahtty]

Hi, I posted this in another section, but I think it was the wrong section, so sorry for reposting.

I live in a top floor flat. In the bedroom, there are damp marks on one wall which are circular in shape, halfway down the wall.

They appear when it is raining and disappear over time. Does anyone know what is causing this and how to fix the problem?

It was raining this morning and the damp spots have returned to the inside wall. The damp spots are always at the same place, I can only assume that it is getting through the brickwork (although I may be wrong as I am no expert, but the spots are always appearing at the same place!!)

I have a couple of questions:

1. Is this causing long term damage to the brickwork?
2. How would I go about fixing this?
3. Would it be ok to use a waterproof sealant paint on the inside walls to prevent the damp spots from appearing? If this is ok, would the dampness just evaporate away from the outside? Would doing this cause any long term damage?

Any help would be greatly appreciated.

 

[mothra]

Hiya Kahtty,

Have you had or the flat complex had cavity wall insulation installed previously? Is it cavity constructed or solid walls etc?

My Mothers bungalow is cavity construction and suffering from circular damp spots with efflorescence aswell, and they seem to be caused by a bridge of the cavity from voids left by the cavity wall foam! causing a bridge for water to get to the internal skin.

Just a thought

 

[kahtty]

Hello Mothra,

I am not sure about the cavity wall insulation, I have only been in the flat for about 4 months now. The building is about 100 years old I believe. How would I find out?

 

[masona]

My Mothers bungalow is cavity construction and suffering from circular damp spots with efflorescence aswell, and they seem to be caused by a bridge of the cavity from voids left by the cavity wall foam! causing a bridge for water to get to the internal skin.

It may not be the foam bridging although not unheard of, it could the lazy bricklayer mortar dropping in the cavity, I used to use 2" timber batten with rope to prevent this happening.

 

[masona]

I am not sure about the cavity wall insulation, I have only been in the flat for about 4 months now. The building is about 100 years old I believe. How would I find out?

The cavity wall was introduced in 1900 century in the UK, drill a small pilot hole with a masonary drill bit in the mortar joint and after 4" of drilling you should hit the cavity gap, if it doesn't then you have solid wall

 

[JohnD]

kahtty
(this is your post - mothra is hijacking you)

If the house is 100 years old it will not have a cavity therefore will not have cavity insulation or wall ties.

However it may well have lime mortar, perished bricks, leaking gutters or missing pointing.

Have a look at the outside of the wall and tell us what condition it seems to be in.

Go outside during heavy rain and see if water is dripping or running on it.

Also look for signs of internal condensation causing damp.

edited - bah!
how thick is the wall (measured at a window or door opening)?

 

[kahtty]

I have a flat roof and I will take a look when I get the chance. Theres no internal condensation, only these bloody damp spots!!

The damp spots appeared this morning when there was a bit of heavy rain, I looked out from my kitchen window and the rain was hitting against the outside wall, therefore I would assume that there is something wrong with the brickwork (this is just a guess)

If this is the problem, would it be ok to use an internal waterproof sealer paint? Would this just be hiding the problem or would it be ok to do this?

Thanks.

 

[JohnD]

The correct thing would be to repair the wall.

Otherwise the wall will be wet (and get worse) and the damp will come out somewhere else.

It might just need repointing, a common and simple job that your friendly local builder could do.

It could also be a dripping gutter or broken downpipe, that is also common.

 

[mothra]

JohnD

I am certainly not hijacking Kahttys post at all, i am simply saying of a similar situation!

Get a life

 

[JohnD]

Sorry.

I had the impression you were adding on a problem with a different cause.

Where can I buy this "life" you mention?

 

[Nige F]

According to a poster I saw , they`re giving it away free @ a chapel near you.........but it didn`t say how much per hour the wages of sin were