Is this damp from outside or is it a heating system leak?

[blueharvester]

We bought a new build house 3 years ago and before we got the keys we got the builder to add a sunroom extension. Shortly after moving in we noticed damp on the plaster above the skirting boards at just the point on the wall where the sunroom attaches to the main wall of the house. After much investigation we think it may be one two problems - damp coming in from the outside brick, or a leak in the central heating pipes running under the concrete floor.

Below is a time-line of the problem along with some photos. Apologies in advance for this being a long winded and pedantic post, but I wanted to provide you with as much info as possible.

December 2006 (3 years 4 months ago)
Sale agreed on new build. Got builder to add a sunroom extension. See pic1 and pic2 for some idea of building work.

February 2007 (3 years 2 months ago)
Got keys to house. We didn't notice it at the time but looking back at this photo we can see a darkened patch of the plaster at exactly the point of the current dampness. In this photo you can also see a trench in the concrete floor which contains heating system pipes.

April 2007 (3 years ago)
Moved into house. Note: We didn't have the heating on from the time we got the house, 2 months prior. Furthermore, the heating wasn't in use until the following winter, thus if the problem is with the heating system, this is the reason we didn't notice damp in the floor before laying tiles.

July 2007 (2 years 10 months ago)
Laid porcelain floor tiles in the kitchen and sunroom.

March 2008 (2 years 1 month ago)
First noticed the damp in sunroom (photo1, photo2). We also noticed similar damp in one of the living rooms (photo1). However, in this other room we had been drying a lot of clothes without any ventilation, so after removing the skirting boards and letting the damp dry out, the problem has never reoccurred.

We notified the builder, and he reckoned it was because the windows were not sealed correctly, so he resealed them. We hoped that this was the solution, but over the next 2 years the damp slowly got worse, and we noticed there was salty/fluffy white deposits on the damp.

February 2010 (2 months ago)
We noticed that the external brickwork looked more damp in the corner where the internal damp occurs (see photos: external, internal). If I trace a line from the peak of the external damp round to the internal wall, I find that it is exactly the peak of the internal damp. The builder came and removed a few bricks from the external sunroom wall but said that the cavity inside was bone dry. He didn't however, take bricks from the main wall of the house.

March 2010 (1 month ago)
Decided to take skirting boards off to see what was going on. Low and behold, the plaster in behind the skirting boards was soaking wet! See photo. The damp seems to spread round the corner too. On the opposite side of this wall is the utility room bathroom in which we removed the skirting boards but the wall was dry.

We got most of the wall dried out with a fan heater but the point at which the sunroom attaches to the main wall will just not dry out whatsoever. The damp seemed to reappear - but we're unsure as to whether it was because we had the heating on or because of the rain.

The builder suggested we tie up the ballcock of the expansion tank in our attic to see if there is a leak. We did that and found that the water level dropped 2 inches in 1 day, suggesting there definitely is a leak somewhere. We also had a plumber out fixing a radiator the other day and he noticed that the water in the radiator was unusually black, which also suggests a leak. He reckoned it could be a leak under the floor.

April 2010 (Yesterday)
I decided to lift the floor tile closest to the damp (we only have one spare tile so I can't lift any more!). I also decided to strip back the plaster. I found that the red external brick was just below the plaster. The red brick was very damp. I can now also see the cavity. See photo1, photo2.

The wall of the sunroom extension seems to be drier i.e. the left hand side of the crack in this photo. This would suggest to me the damp wasn't coming from the floor.

Questions
1. Should the sunroom have been attached this way i.e. with what was once external bricks now becoming internal bricks?

2. Why is the wall also damp round the corner from the main damp? Could the damp soak into the tile adhesive and travel round the floor?

3. Is there any way to prove where exactly the leak in the heating system is so that we know for sure before proceeding to dig up the tiles and the floor?

4. Is this damp coming from the outside in (through the porous brick), or from the inside out (pipe leak)?

5. Could it be a combination of both shoddy brick work and a leak that's causing the damp?

I'd really appreciate your help and opinions on this.

Thank you.

 

[noseall]

I would almost stake my mortgage that the leak is from a pipe. Unless you have an underground spring and a punctured d.p.m!

Brickwork gets wet and then it dries. Simple.

To stay wet and cause trouble it needs a constant supply of water.

 

[blueharvester]

I would almost stake my mortgage that the leak is from a pipe. Unless you have an underground spring and a punctured d.p.m!

Brickwork gets wet and then it dries. Simple.

To stay wet and cause trouble it needs a constant supply of water.

And do you think the leak would likely be under the floor where the sunroom joins the main house?

 

[noseall]

If it a horizontal leak then it would need to be local to the wet patch.

If for instance the pipes carried on vertically up the pillar and were within a partition space then the leak could travel downwards from any point above.

You have also contravened regulations by not having a thermal break between the conservatory and the main dwelling. But that's another matter.

 

[blueharvester]

If it a horizontal leak then it would need to be local to the wet patch.

If for instance the pipes carried on vertically up the pillar and were within a partition space then the leak could travel downwards from any point above.

There are no pipes running up that wall. However, there are some running under the floor from the main building out to the sunroom.

You have also contravened regulations by not having a thermal break between the conservatory and the main dwelling. But that's another matter.

Any more info on this? When you say 'you', you mean 'your builder', right?

 

[foxhole]

February 2010 (2 months ago)
We noticed that the external brickwork looked more damp in the corner where the internal damp occurs (see photos: external, internal). If I trace a line from the peak of the external damp round to the internal wall, I find that it is exactly the peak of the internal damp. The builder came and removed a few bricks from the external sunroom wall but said that the cavity inside was bone dry. He didn't however, take bricks from the main wall of the house.

The photo's in this section show an external drain pipe for discharging rainwater , is this into a drain? the other corner has no apparent drainage? so it looks like external corner is constructed like a swimming pool , no where for rain to go and brickwork for the rain to bounce off up the walls.

 

[blueharvester]

February 2010 (2 months ago)
We noticed that the external brickwork looked more damp in the corner where the internal damp occurs (see photos: external, internal). If I trace a line from the peak of the external damp round to the internal wall, I find that it is exactly the peak of the internal damp. The builder came and removed a few bricks from the external sunroom wall but said that the cavity inside was bone dry. He didn't however, take bricks from the main wall of the house.

The photo's in this section show an external drain pipe for discharging rainwater , is this into a drain? the other corner has no apparent drainage? so it looks like external corner is constructed like a swimming pool , no where for rain to go and brickwork for the rain to bounce off up the walls.

Yes, that external drainpipe is flowing into a drain. There's no drainage on the other side because the guttering on the sunroom runs around to the other side, where there is a drainpipe and drain.

 

[noseall]

Any more info on this? When you say 'you', you mean 'your builder', right?

It is a (professional) builders' obligation to advise customers about building control procedures. Not all do, some just see the ££££.

However, it is the homeowners responsibility to conform to building control regulations and they alone are liable.

In a lot of cases conservatories are built with the existing doors still in place. The homeowner then takes it upon himself to remove these doors at a later date.

 

[blueharvester]

Any more info on this? When you say 'you', you mean 'your builder', right?

It is a (professional) builders' obligation to advise customers about building control procedures. Not all do, some just see the ££££.

However, it is the homeowners responsibility to conform to building control regulations and they alone are liable.

In a lot of cases conservatories are built with the existing doors still in place. The homeowner then takes it upon himself to remove these doors at a later date.

How could we have conformed to building control regulations when the builder built the extension before we even signed the deeds? Surely it is the responsibility of the builder? Anyway as you say this is a different matter, I just need to get this damp sorted.

 

[noseall]

How could we have conformed to building control regulations when the builder built the extension before we even signed the deeds? Surely it is the responsibility of the builder?

I presume the connie is attached on the rear elevation surrounding the patio doors visible?

Who removed the patio doors?

Was it signed off in this state i.e. without patio doors?

Or, did you remove the doors later on?

 

[blueharvester]

How could we have conformed to building control regulations when the builder built the extension before we even signed the deeds? Surely it is the responsibility of the builder?

I presume the connie is attached on the rear elevation surrounding the patio doors visible?

Who removed the patio doors?

Was it signed off in this state i.e. without patio doors?

Or, did you remove the doors later on?

Yes, it is attached to the rear elevation surrounding the patio doors. It was the builder who removed the patio doors. We signed the deeds once the house was fully completed i.e. with sunroom on and fully plastered.

 

[noseall]

I would be interested to know if b.c. saw it without the patio doors and was it a request from you (the homeowner) to have the doors removed or did the builder simply remove them?

Was there any discussion about the doors?

 

[alittlerespect]

Hi

Just a quickie as its getting a bit late - The detail you show in photo's 18 -20 of the open cavity end is totally wrong and you will get problems with penetrating rainwater backtracking to the exposed end of the cavity shown in your photo's, hence one reason for the damp at this location, and this would account for the problem you are encountering.

One question - is the internal floor level below the external dpc level.

You need to keep an eye on the level of water in the Feed and Expansion tank to the central heating system - if you are losing a lot of water this would be indicative of a leaking pipe or more likely join in the pipe. Also the line of damp on the external wall below dpc level would suggest that the brickwork is saturated and you may well have a leaking pipe contributing to the problems.

Regards (time out, or should that be out of time!)

 

[maltaron]

Looking at the piccy,s I would suggest that the joint between the the sun room and main house has not had correct DPC installed. I would think that the sunroom DPC butts against the main house wall and is not lapped over the main DPC, therefore is not a continuous damp barrier. That I am certain is your problem. As a new build surely you have an NHBC 10 year warranty-get the builder back to sort it.

 

[blueharvester]

I would suggest that the joint between the the sun room and main house has not had correct DPC installed...That I am certain is your problem.

I would almost stake my mortgage that the leak is from a pipe.

Now I'm really confused