Damp in oak internal wall

[Plus1]

Good morning everyone, I am looking for some help/ suggestions on this. we have an internal wall that is very wet as can be seen in the photos attached, the panels above are wattle and daub with gypsum on top and emulsion, the underneath panels Are concrete blocks on a damp course with gypsum and emulsion, the posts themselves are sat on blue engineering bricks.
Now I understand using cement is a no no anywhere on the outside as water gets trapped, but internally as this has a damp course stopping any rising damp why is it so wet?
Any comments will be appreciated and thanks in advance

 

[Cubist]

Hi there,
The pattern of water discolouration suggests damp rising from ground level. Can you confirm that the the feet of the posts are damp/wet. Capillary action may be drawing water from ground level and then, via the mortice and tenon joints, into the connected timbers.

Can you provide some external photos of the same wall please and indicate whether this wall faces the prevailing winds/weather? Is the plinth, on which the posts are standing, above ground outdoors?

 

[Plus1]

Many Thanks for your time replying I have attached a photo of the other side of the wall it is an internal wall. floor level is the same both sides, from what I can see, damp course runs under the block work and blue bricks.

 

[Cubist]

Thanks for the additional picture. Seems clear that the block-work was installed a long time back and so should be throughly dry. Assuming there is a DPC membrane of some sort beneath it the damp rising from the ground below should be limited. However, if the DPC was bridged by the plaster that may provide a route for water to get to the base of the posts. Have new floors been laid in those rooms recently? Concrete or limecrete? What were/are the rooms used for?

 

[Plus1]

The floors on both sides of the wall are concrete with damp course and insulation beneath possibly laid at the same as the block work under the beams, the rooms are empty and inhabited but fairly dry… I’m beginning to wonder, could damp be entering from the external wall and be tracking all the way down and across the block work? This would be approx 10 feet, many thanks for everyones time on this

 

[Cubist]

I’m beginning to wonder, could damp be entering from the external wall and be tracking

Its feasible. I would certainly be checking the condition of the external caulking around the sides of the infill panels outdoors, particularly those around the posts to which those internal timbers are connected. It's worth paying particular attention to the pegs used to secure M&T joints in those posts and the timbers joined to it. The pegs can operate as capillaries that allow water to penetrate the joints - oftentimes the pegs may be missing, desiccated beyond effective use or broken - they need to be in good condition, tightly hammered into their holes and occasionally painted with a little linseed oil. Don't confine your examination to just the level at which the observed damp is seen indoors, the origin of the water problem may be anywhere above that level.

That said, tracking to that distance from an external post would be very unusual but not impossible. However I would expect there to be a gradient of damp originating near the external walls that gets progressively drier, and less evident as it moves into the room.

I notice in the pictures what appears to be a lead service pipe rising from the floor. Was this by any chance a water service pipe? If so, how was water distributed through the house from there? What route was taken by the old pipe-work and is there any chance that water may still be draining from any pipes that have not been removed?

 

[Plus1]

Many Thanks for all your info Cubist, the outside doesn’t look to bad, not compared to other places where there isn’t leaks, but could still be the problem, I will give the outer walls a going over and see if it’s a fix
The water pipe has been used as ducting for electric cables I believe
Many Thanks for your help

 

[Cubist]

What I find rather intriguing is that the distribution pattern of the damp seems to be rather odd as it appears to be restricted to just one side of that wall. It may be that the photograph of the other side is misleading, but I would have expected a broadly similar distribution of water stains on bother sides of each of the timbers. That implies that the source of the water is located inside the room.

 

[Plus1]

Yes it always seems to be soaking wet 1 side and not the other, you would think it would find its way through the 4” wall to the other side before travelling approx 10ft, if it is coming from the outside,

 

[malcolm]

I've been replacing cement render with lime recently due to damp problems. I've never had to deal with concrete blocks.

It looks like water is trying to escape from the wall and with everything impermeable the only place it can escape is through the wood. Forget any modern theory of damp courses. Water has clearly got in and you have wood that you don't want to get damp.

I hate cement and if it were me I would rebuild the lower panels in bricks and lime and then lime render. That would almost certainly fix the problem. Water would make it's way out before it gets to the timber frame.

It's likely that just removing the plaster and re-plastering the concrete blocks with lime will also work. Gypsum seems especially impermeable. But I've not tried that so do report back if you do that.

 

[Cubist]

My schoolboy physics is more than just a little rusty these days and that, perhaps, is one of the reasons why this thread has proven a rather odd conundrum. To recap;

• The timber posts are mounted on engineering bricks and the concrete floors have a DP membrane of some sort so rising damp from the earth below should be minimal and what there is should be fairly uniform from one side of the wall to the other.
• Rainwater could feasibly be tracking along the tops of the block-work from outdoors but then one would expect both sides of the wall to exhibit similar damp and staining patterns.
• There are no active water sources in the room that may be leaking.

How then could the timbers get wet enough on just one side to exhibit staining but the other side in a separate room show none?

Ferreting around in the darker recesses of an education long past produces only one theory, beyond those already discussed, that may explain the observed circumstance - convection.

A heat source in that room would have the effect of drawing colder, damp laden, air toward it. Any damp trapped in the block-work during its construction would therefore migrate toward that heat source and find its way into the more permeable materials of the timbers and plasterwork where it would ultimately evaporate into the atmosphere of the room. The only possible evidence, thus far, to support this postulation is contained in the OPs first photograph in which there are indications that a radiator of some kind may have been mounted on the lower central panel.

As theories go, I know the above's a bit thin, but until the OP finally gets to the root of the problem and can provide a more reliable explanation it will at least do to stop my moments of empty headed puzzling over the problem.

Has it stopped raining yet?

 

[Plus1]

Thanks guys, it is an odd one, usually damp is fairly evident where it’s coming from, where as this is or has been soaking wet without being able to see where from, it’s drying out well at the moment, so plan is to have a go at the rear outside wall over the summer, see if that eliminates it.
Appreciate all the comments on this and many thanks