Has this building had a visit from a cowboy damp proofer?

[TCB746]

Hi,

I've bought a 1930s property that had some damp on survey so the owner decided to have damp proofing done. (not sure I would have bothered myself as it clearly penetrating damp caused by chimney / loose tile and old rendering that needs replacing)

Having moved in I'm confused by what the company have had done. There are 4 x 15 mm holes drilled into the skirts in the upstairs bedroom that go as deep as the brickwork. I guess to ventilate the wall?

Externally there are 2 lots of 9 x 12 mm vertical holes going up to a height of about 4 feet about 5 feet apart which the damp guy has drilled . (pic attached - the second set of holes are just behind the down pipe) From sticking wire in these go back 5 - 6 inches with no resistance. ( I have 9" solid walls).

I would have expected these to be filled with damp cream and plugged, surely? And why are they going up instead of along...?

I've had a look at the guarantee that the previous owner has given me - I can't find any trace of the company online or on Yell but there is an 0800 number... I rang and asked the guy who answered if I could fill the holes, he was quite abrupt said I had to leave them 6 months first... he didn't answer with the company name either which was a bit odd.

any suggestions? Surely having holes would lead to more damp...? Or is it a case of ventilating the wall to allow it to dry out and I'm being too supicious?

thanks

Damp Injection holes?

• TCB746
• 24 Feb 2014
• 1

 

[rjm2k]

no expert but it does look like snake oil.

as long as it's no worse and you know what really needs to be done and it's not too expensive I guess it's not an issue. just another example of ticking a meaningless box which needed ticking due to a meaningless survey

 

[TCB746]

Yes that's my feelings, bit on the off chance that it has been done right I'd rather check before messing it up.

 

[loply]

I'd be flabbergasted if the surface area of those holes is going to help dry out the wall.

Rising (and indeed penetrating) damp is a competition between the water absorption rate and evaporation.

Water evaporates out of the wall across it's whole surface area, faster or slower depending on conditions, but is getting in again via rainwater, leaking gutters, human lifestyle, etc. Which one happens faster determines whether the walls are getting wetter or dryer.

Compare the surface area of the exterior of your house to the size of those holes. You may have increased the surcace area by what... 0.025%? Plus the holes may just help water get in and stay in.

All in all the damp competition is completely unaffected by what's been done, I'd say. He may as well have done some kind of sun dance in the front garden.

Make sure you ring him and give him an earful for being a total moron.

 

[Johnmelad]

http://www.askjeff.co.uk/rising-damp/
http://www.architectsjournal.co.uk/...a-myth-says-former-rics-chief/5204095.article
http://www.heritage-house.org/the-fraud-of-rising-damp.html
http://www.rics.org/uk/shop/The-Rising-Damp-Myth-17888.aspx
http://yorkshiretimes.co.uk/article/Rising-Damp-in-Old-Houses-Its-just-a-myth
http://buildingdoctor.com/rising_damp/rising_damp_myth.php

 

[TCB746]

Thanks all for replies, yes am already aware of the rising damp myth although those vids have been interesting viewing thank you.
I was just wondering if the holes were to combat the penetrating damp but looks like I've got my answer : )
So what's best to plug those holes? Not looking forward to the estimates for rendering that entire side of the house... : (

 

[Flyboytim]

I'd hazard that these vertical lines of holes were done as part of the survey, not the treatment holes, which are clearly in the exposed mortar course at the bottom of the wall in the image.

As part of the survey, the vertical drillings would attempt to show the dampness profile of the walls, possibly with some laboratory report to show the moisture content vs. the height in each wall, to confirm the presence of rising damp. Whether this was bona fide is anyone's guess.

They are a likely source for water ingress and should be plugged.

There looks like some staining on the concrete flagstones on the path between the vertical drillings. There may have been a historical leaking gutter problem before, which has caused water to splash off the path into the wall above the original DPC, causing penetrative dampness. The render on the wall above this would have prevented the wall from drying out adequately.

I'd therefore put the render at fault as well.

 

[TCB746]

There are no other holes, I did a thorough check, afraid they are just marks on the wall that can be seen on the pic.

So use expanding foam and silcone sealeant to plug or use proper damp proof plugs that I've seen on other properties?

 

[Flyboytim]

You say that the holes go back 5-6 inches in a solid wall? I guess foam and silicone would do the job - foam alone, and touch up the masonry paint would probably be no worse.

 

[loply]

I'd hazard that these vertical lines of holes were done as part of the survey, not the treatment holes, which are clearly in the exposed mortar course at the bottom of the wall in the image.

That was my first thought, but, he said he phoned the guy and he told him to leave it 6 months to dry out?

Also seems like a few too many to be necessary for testing purposes...

 

[gregers]

dont suppose theres a chimney on the other side of that vertical line is there??

if so im suspecting its a vertical dpc on the side of a stack.

 

[wessex101]

The line of vertical holes on the photo looks like an attempt at a vertical DPC. It is common to inject a vertical DPC if only part of a wall has been treated so I'm guessing they only injected the low level horizontal DPC between the vertical holes and the downpipe.

No comment on whether the work was necessary or quality of workmanship. I have to say the independent evidence regarding rising damp from bodies such as Building Reseach Establishment, British Standards Institute etc. is a lot more compelling than the likes of Jeff Howell and the other Rising Damp Myth brigade who all seem to have a book or a service they are trying to flog on the back of it. I certainly would not like to try and build a new wall without a DPC.

Yes the holes can be filled.

 

[TCB746]

No, the chimney is about 5 ' to the left of the first set of holes.

The holes do seem to line up with the internal measurements of the lounge on the other side though...