Rising damp, advice please

[Phlebas]

I used to be the head partner of the Scottish professional department of one of the big surveyors. My equivalent in the building surveying department would regularly throw away the two pronged moisture meters if he found any of his staff using them (trained by other firms, t’chah, charlatans, every one of them). They are simply unreliable (at best) if used in masonry, unless you really know what you are doing. He was of the opinion that relying on one by itself was tantamount to an admission of professional incompetence.

 

[toolsntat]

Pictures 4&5 look to be showing cables clipped under the render stop beading which generally has a bottom bevel to throw water away from the underlying bricks and mortar.
Surely this could allow the water to track back onto the bricks and mortar (possibly above any dpc ?)
Cheers Andy

 

[AJB Temple]

If you are still o the opinion that there is in fact damp (questionable) I think I might be tempted to chip off some render and see if you can locate the dpc. Is the render bridging the dpc?

 

[Woody2Shoes]

....there is no trace of damp inside the house by mould, smell or feel....

On that basis, I would strongly question whether you have any kind of problem worth worrying about! If it were me, I'd forget the whole thing.

I'm guessing that the DPC will be pretty much at the same level as the horizontal render bead. The render appears sound. The pointing does look a bit odd/tired but seems sound enough. The ground level appears to have been raised in the fourth/fifth pictures - where there's gravel/paviours - normally you'd expect to see 150mm (two brick courses'ish) between DPC and ground - to reduce risk of backsplashed rain hitting the wall above DPC (but the masonry above DPC appears to have proper rain protection from the render in any case).

Seriously, I'd find something else to occupy my mind. Cheers, W2S

 

[MikeG.]

Again, just a quick skim of the photos (I'm really busy)...... if the bottom of the render is at DPC level, then there are some places where your ground level is too high. A DPC must be a minimum of 150mm (2 brick courses) above ground level. Ideally, too, your ground adjacent to the house shouldn't be hard, because this allows rain to bounce up the wall. So, although you seem to have no damp issues, you do have potential problems and should consider lowering the ground level and changing to a porous surface.

 

[AJB Temple]

House near me. Wettish surroundings. Seems to have held up OK.

 

[MusicMan]

Thanks again for advice. I have just told the firm that we are not going ahead with their quote.

Andy/Mike thanks for the advice re 2 brick courses above ground before the DPC. The gravelled part is easy, as it is just a border bed with a few ferns and box bushes. The gravel is deep and some can easily be removed. With the block paving, I can remove it along the wall and replace with gravel at appropriate depth, and also re-route the cables as suggested.

Most helpful.

Keith

 

[JollyJ]

So this is in my house rather than workshop (ok a part of the house is a workshop!) but couldn't see where else to ask you experienced builders/architects if you can advise me on due diligence.

Had a cold call from House Guard, offering a damp survey to see if my insulation (blown rockwool) was allowing damp through, so thought no harm in getting their report. The guy came, equipped with a two-point moisture meter, rather the sort of thing one uses for wood. I saw him do the measurements so there was no sleight of hand. The readings on the old part of the house, about 60 years old, were: 30% in skirting boards, 15% on walls immediately over, dropping to 8% 50-60 cm above, dropping to negligible at 150 cm. The 20-year old part of the house (a big extension) showed no damp problems.

Conclusion was that there was no problem with the rockwool insulation, but that the 1960s-era bitumen damp-proof course was failing and needed replacing. This seems reasonable to me, is this right?

Of course they want to do the work. The walls are brick, with 1 or 2 courses visible before the DPC, this was bitumen covered originally but this has cracked and the mortar needs pointing.Above this the whole house is stucco covered, which needs some attention but is generally fairly good condition. The process would be drilling holes in the mortar, injecting the product "secoMUR", repointing brickwork all round then using black secoMUR to seal and replace the bitumen up to the start of the stucco.

The perimeter needing treatment is 30 m. and the price quoted is £3000. It would be about 2 days work for the team (no idea how big the team is).

My questions are

1. Does the diagnosis seem correct?
2. Is this the appropriate treatment for replacing a DPC in an existing building?
3. Is the price quoted about ballpark, cheap or expensive?

I'd be very grateful for guidance, comments and cautions.

Keith

Hi Keith

I was hoping you might have an update on this please?

I am in a very similar position with my moms Bungalow. There is damp and it's in quite a few of the walls. I had a secomur guy come out and assess the issue and he stated that it was the same issue with the original Bitumen stated as having failed and rising damp via capillary action.

A lot of the responses in this thread were that 'capillary action damp' isn't a thing which I don't think is helpful given each person has an opinion and each house is unique in location and problem symptoms. Capillary action in bricks is a real thing. It just is.

I need to know how to test for a leaking pipe because the guy who assessed the property stated that it wasn't a leaking pipe because there would be water in the carpet (there isn't water and the tiles aren't lifting off the floor) and the pressure in the central heating is constant.

I've uploaded a diagram of the property, it's all one level. The damp is mainly located in rooms 17, and 19 and 23.

There is a french drain running along the side of the building south of the diagram (next to rooms 6, 9, 11, 12, and 23) with the plot of land being on a small hill and with a drop to the adjacent property at about 2 meters from the french drain.

I raised the french drain and it being on a hill with the damp guy and he said that it's still possible to have a rising damp issue even with these solutions currently in place (on a hill with french drain).

I see you updated the thread with the solution of:

re 2 brick courses above ground before the DPC.

Did this work?

I do think that the random bloke who pitched up selling the damp solution was wrong and just looking to sell you a solution to a problem you didn't have but that's not to say that the solution might not work for me.

My issue is that I do believe that there is an issue but I'm not sure if it's a leaking pipe or actual rising damp and this thread is as close to the property description as the one I'm managing.

 

[JollyJ]

Here's a DIY option that I actually quite like and looks remarkably like the issue I'm having

I will go into the loft now and see if there are any leaks coming down as there is some damp quite high up on the toilet wall.



Edit: I think the damage high up the wall at 6 foot height is only there because of the tiles up to 4 and a half foot (ish) and the water essentially is pushed up further.

 

[HappyHacker]

I have experienced rising damp and also poor surveyors:
Many years ago I sold a house and the surveyor said there was raising damp in the back wall and it needed a DPC. The house was on a slope high at the front and the area he found damp was at internal floor level at the back 5ft above the outside ground level with a vented open space of the same height under the floor. It was caused by a pinhole leak in a radiator!

My current bungalow was built in the 50s. There is a damp proof course in all the external and internal brickwork. They put the scratch coat of plaster over the DPC and then laid the internal concrete floor to DPC level. The floor DPC is on top in the form of a thin layer of bitumen with plastic Marley tiles on top. Then the skirting was put on and the finish coat of plaster. Over 50 years all the internal skirting and some of the door frames have rotted at the bottom where the damp has tracked through the concrete floor and the up the scratch coat. Digging out the scratch coat below the DPC and a painted DPC on the exposed wall and concrete has solved the problem. The house never smelt or felt damp.

Totally agree with others about the use of with two pin damp detectors. They measure the resistance between the two pins which can be affected by so many things on a building materials that they are almost useless.

 

[joncooper27]

Hi
I’m in agreement about damp as well a big advocate of breathability, lime plaster and pointing and breathable paint like clay paint on old properties.
Are you sure the lower brick are not a different type of brick like an engineering brick. Is your property pointed with lime mortar?
I’m in the process of repairing some of my lath and plaster ceiling rather than ripping down and replacing with plasterboard.