Damp proofing

[Fitzroy]

like most things in life it’s actually quite complicated, whereas business and people like simple problems and solutions. A business model has been developed that can be adopt by anyone, the bias in the model is self supporting.

Contractor X tunes up sees damp at the wall base, sticks tool in wall to confirm suspicion, sells standard solution, workmen in place in a week smashing, drilling, filling, tanking, papering. Two weeks later damp is ‘gone’ another happy customer. Bias that this is the solution confirmed.

In reality the problem is hidden or masked, and could likely have been solved with much less disruption and cost, although over a longer timespan, through identifying and eliminating the source of water ingress/penetration.

 

[niall Y]

Surely, if water did not rise up a wall through capillary action , then there would be no need for a damp course in buildings.

People can get very hard core about the ins and outs of dealing with damp., And I am well aware of the mantra that lime plaster and lime mortar solves everything. But it is patently obvious that this is not the answer to every thing damp related.

One has to look for where the water coming from. If it is driving rain on a Victorian end of terrace wall. then lime plaster and lime repointing may well supply the answer. Failing that the addition of a lime render may also work.

However I have worked on buildings in more exposed areas where following this purist approach has not solved the problem.. One does not always wish to live as our ancestors did with yearly applications of lime wash to the outside of the buildings or restrict oneself to using breathable clay paints on the inside. Where every time the wall gets damp the paint gets several shades darker. And where using wallpaper is a no, no. The last big gun left to the purists in this instance is to batten out the outside of the wall apply slates

 

[Adam W.]

I don't think it is ambiguous or open for debate, "Rising Damp" as the lay person understands that term does no exist, capillary action will allow damp to rise up into a brick or wall structure, but not to the extent of more than one brick, the mortar joint will prevent that.

I wouldn't be surprised if there were a few RICS surveyors arguing the case to try and cover their butts.

What's true rising damp then, if rising damp doesn't exist ?

 

[MikeJhn]

I wouldn't be surprised if there were a few RICS surveyors arguing the case to try and cover their butts.

What's true rising damp then, if rising damp doesn't exist ?

As you quoted my post, Is that question directed at me? if so I don't understand.

 

[Adam W.]

Yes, you said rising damp doesn't exist in your earlier post, but the two chaps in the video mentioned true rising damp, so I was getting confused by the two and as you are a surveyor I thought you might know the difference between rising damp and rising damp.

And, I'm pretty sure that amongst surveyors who in the past advised all sorts of tanking, chemical DPC and other remedies, the rising damp debate is still raging. This is also mentioned briefly in the video, so perhaps as building pathology and construction in general is forever updating itself, the knowledge on rising damp is still evolving like everything else is.

 

[Fitzroy]

Surely, if water did not rise up a wall through capillary action , then there would be no need for a damp course in buildings.

People can get very hard core about the ins and outs of dealing with damp., And I am well aware of the mantra that lime plaster and lime mortar solves everything. But it is patently obvious that this is not the answer to every thing damp related.

One has to look for where the water coming from. If it is driving rain on a Victorian end of terrace wall. then lime plaster and lime repointing may well supply the answer. Failing that the addition of a lime render may also work.

However I have worked on buildings in more exposed areas where following this purist approach has not solved the problem.. One does not always wish to live as our ancestors did with yearly applications of lime wash to the outside of the buildings or restrict oneself to using breathable clay paints on the inside. Where every time the wall gets damp the paint gets several shades darker. And where using wallpaper is a no, no. The last big gun left to the purists in this instance is to batten out the outside of the wall apply slates

Aberdeen houses are designed with and internal void between the granite wall and the lath and plaster. Additionally the stones (skenes) in the wall are dressed with the upper surface sloping towards the outside of the wall. Both of these features are to help with the management of moisture from driving rain. It’s really interesting to try and understand why houses were constructed as they are.

 

[Adam W.]

Interestingly, I'm taking the RICS Certificate in Building Surveying Practice and they list rising damp as one of the common defects which can be found in buildings in the "Building Pathology module".

Funny really, because the video that I posted earlier is part of the teaching material from that module.

 

[niall Y]

Aberdeen houses are designed with and internal void between the granite wall and the lath and plaster. Additionally the stones (skenes) in the wall are dressed with the upper surface sloping towards the outside of the wall. Both of these features are to help with the management of moisture from driving rain. It’s really interesting to try and understand why houses were constructed as they are.

An interesting observation bearing in mind the granite itself is pretty impervious to water.

The older properties in this part of the country, however, have no such refinements. Their walls are usually about 2 ft thick, with rough stone to both the inside and outside with any remaining inside void, filled with stone debris and mortar. In the worst case scenario the stones are bedded with earth, and only the outside pointing is lime mortar. One farmhouse I worked on, the previous owner had framed the outside walls with galvanised corrugated iron in a desperate attempt to cure the damp problem.

 

[Bingy man]

It's a bit dry, but worth a watch.

A very interesting video/ I recall many years back mid 70,s this was done to my moms terraced council house along the outside walls they drilled and injected a chemical dpc, and 1 meter of plaster hacked off then rendered. 12 months later the kitchen was black with mild and condensation literally trickled down the walls.

 

[thetyreman]

It's an interesting subject for sure, I think a lot of the knowledge was lost when working men died in WW2 when we rebuilt the country with cement mortars, although there seems to be a crossover period where some builders still used lime even into the 50s, also I think cavity wall insulation is bad as well especially the minging white fluffy stuff, because if it gets wet via cracks in external cement mortar, it will make a wall feel really cold and damp, it will pretty much never dry out, surely the whole point of a cavity wall is airflow which dries out any water inside? as regarding a DPM, it makes sense to have one rather than not have one just as a precaution, but a lot of the problems come from repointing with bloody cement mortars when it should be lime instead, always do a like for like repair.

 

[Bingy man]

I’ve been involved with my friends house for a little over 2 years now . Its been gutted and stripped back to brick , the ground floor was rendered internally approximately 1mtr up and along all of the external Walls, the tell tale signs of the 8 or 10 mm holes on the exterior walls outside give further clues. We were surprised to find this rendering on the 1st floor too but this I’m assuming was done to try and combat the solid outer wall from collapse ( the house has no foundations) and was built compacted ground and finished off with black ash . We also took down the 4 chimney stacks from roof to ground floor and the biggest surprise here was were all filled in at some point with rubble , ash brick and mortar debris- ive never seen this before. From what I could determine the damp was caused by the ground level creeping above the air bricks and the 4 rainwater down pipes ( 2 front 2 rear terminating a foot or so below ground level a few inches in front of the brickwork. There was no attempt at a soak away. The blocked chimneys could of added to the damp .

 

[Adam W.]

After having read all of the RICS surveying course material, the RICS do not deny the existence of rising damp and refer to it continuously throughout the building pathology unit.

I would imagine that the RICS think it is not conclusive and that the subject requires further investigation.