Penetrating Damp

[hughsie]

We live in a 150 year old 3 story house that is exposed to the south west and takes a battering when it rains. The walls of the house are built from stone and do not have a cavity. We are experiencing damp patches on the western and southern facing walls. I doubt that the damp is being attracted from the inside, the rooms affected all have different usage.

The damp is not running down the walls but is visible in patches causing plaster to flake and wallpaper to lift, there is also an occasional damp smell.

I have been told that stone walls naturally soak up water which runs down and evaporates. If this is the case then the exceptionally wet summer has not allowed the walls to dry.

My questions are:

1. Do stone walls handle rain in the way I have been told?
2. Is there anything I can do to stop the damp?

Thanks, David.

 

[Roger H]

Bump..

But probably covered in the 'Damp Sticky 'Faq's'.

I'd suggest, yes it's very wet this summer and hard for the normal drying out process to take place; and, maybe there is some extra ventilation needed.

 

[Penners]

Follow this link to one of the new RICS Factsheets - this one on damp. Might help you.

http://www.periodproperty.co.uk/pdf/RICS_Dampness_Factsheet_V3.pdf

 

[shelli]

Hi hughsie

we have south facing gable end wall - and experienced the same type of damp patches you describe

Our house is stone construction too - v thick walls with through stones - essentially if the outer stone gets wet it can travel through gaps into inside - we got extra wrinkles waiting for our newly plastered bedroom wall to dry out - when there were still round damp bits after 8 weeks we gave up waiting and drylined it and ventilated with 4 internal vents - life is too short to worry about a bit of that type of damp in an old house - cover it up - ventilate it and move on !! -

Your other option is to weatherproof your external wall with something like slates - we didn't go down this route because it was like that when we bought it and we hated the look of them (we also figured that battens fixed into the stone and mortar to hang them from would breach the fabric of the building and was almost bound to allow water in - so seemed opposite of what we wanted to achieve).

we have spent 18 months digging french drains, repointing stonework, rebuilding chimney stacks - digging out rotten sandstone pieces and pulling pieces of mouldy plastic out of stud walls to get our house dry - you get to a point where un oeuf is un oeuf

Shelli X

 

[Nemesis]

Hughsie, it's probably small gaps in the pointing/ mortar which is allowing water to get in. Check the pointing.

If it's not lime but cement, then you have bigger problems.

Saturated walls can take a considerable time to dry.

Send me a PM and I'll talk you through stuff if you want.

 

[Gervase]

It's highly likely that the wall was once protected with a roughcast render or simply many coats of limewash applied every couple of years over many deacades. Either of these adds an additional protective but breathable layer to the wall and ensures that any small gaps in the pointing are sealed. Sadly the fashion for bare stone means that many such walls have now been stripped naked and are now vulnerable to driven rain.

 

[u102363]

We have an 18th-century stone farmhouse which is currently undergoing some repointing in lime, to get round penetrating damp in a downstairs bedroom on a west-facing gable end. A battering in the rain? We get uphill hailstones here!

The only reason the damp wasn't visibly running down the gable end wall was because there was studwork covering the inside... but the damp was still creeping round the ends of the studwork into the adjoining walls too (gypsum plastered). Not good to keep the damp walls covered up as it seems to have caused a couple of joists to rot where they sat in the stone above the stud wall. External stonework on that wall seems to have been pointed in cement, with not much left behind it. I can understand covering minor dampness with ventilated studwork, but the amount of water running down behind the polythene was getting uncontrollable. Heating in the room was pretty ineffective due to the poor thermal capacity of the walls, so we were waking up to temperatures of 11 degrees C in the bedroom earlier this year!

The north-facing adjoining wall had an ensuite bathroom against it, and externally was painted in flaking exterior paint over limewash. When the bathroom mirror was taken off, the wall was so wet that the gypsum plaster could be scooped out with fingers. Most of the wall has now had its mortar chiselled out, and is nearly ready for filling and pointing. The wall had been damp enough so that the lime mortar within large sections had mostly trickled away over the years, and the builders found a couple of large voids with no infill left.... as well as large sections of the wall being looser than a dry stone wall! This wall is going to be pointed in lime soon, after paint removal by careful sandblasting. Hopefully we won't need to put anything on top of the stone afterwards, but time will tell. Inside will be lime plastered. The stonework inside is looking like it is reaching a satisfying level of dryness at last, but with 2-foot thick walls it will take time to dry properly (or to know it hasn't worked!).

Other contributing factors we found were that part of the ground outside had come up above the floor inside, part of the wall to the rest of the house seems to be a retaining wall (so no avoiding the underground nature of it there), and a couple of badly blocked up openings (complete with concrete blocks and wooden lintels still in place) in one wall. An attempt at injecting a damp-proof course has been made about a foot above floor level, and several layers of plaster had been applied to try to hide it all over the years, together with 4 layers of tiles in one place. There was even some leaking pipework when the bathroom came out (the shower tray definitely leaked). We have a balcony on the south side which seems to be funnelling water in too, and some cracked cement render underneath that which can't be helping either. Of course before we stripped it all back we assumed it was caused by rising damp, but it was nearly to ceiling height!

Anyway, if you have gypsum plaster inside, and worse still cement pointing outside (we did), then I am rapidly coming to the conclusion that stripping it back and getting it filled in and refinished in lime has to be the only way to go. Not cheap for us, but we are getting a lot of satisfaction watching decades of poor repairs being taken away and being redone "properly."

Good luck!

 

[Schoolmarm]

u102363, who did you end up using for your pointing and building works? Are they any good? And what kind of rates are they charging?

 

[u102363]

I have sent you a Private Message with their details.

Cheers,
OB.

 

[Schoolmarm]

Thanks for that, can't believe another PPUK person lives so close. :shock:

 

[FamilyWiggs]

Sounds like another regional PPUK gathering in the offing...

 

[Schoolmarm]

Sounds like another regional PPUK gathering in the offing...

Ah well, us northerners don't arrange things as such we just "knock on" or "drop in for a cuppa" 8)

 

[Penners]

If you knock-on, do you have to have a scrum down?

 

[Schoolmarm]

As soon as the knock on has finished, yes we usually scrum straight down. Can be a bit awkward sometimes if the knocker onner is a lot bigger than the door opener.

 

[Penners]

Fun though.