My Irish Cob Farmhouse Project

[simon.d]

For the last 6 months I've been working part-time on an old farmhouse in the County Waterford in the south east of Ireland. The house itself is at least pre-1800, if not pre-1700, made of mud, mostly, with a thatched roof covered by corrugated sheeting. The original structure comprised of a two roomed cob building with a centrally placed hearth. Over the years a few additions have been made including a stone addition to one end circa 1900, and a couple of concrete additions 30 or 50 years ago. My work to date has been mostly internal stripping, and de-cementifying the place. But plan to have it habitable within the next six months..

My biggest worry is that a portion of the back cob wall is very damp and crumbly, possibly as a result of the thatch eaves being removed 40-50 years ago to cater for block work supporting the corrugated roof on top, exposing the wall to the weather. Externally it looks like this part of the wall has been patched up with shuttered concrete (have yet to properly investigate but can see the form-work lines). My plan is to repair the wall (where needed) with cob, and have already made a sizable batch of cob blocks that are almost dry and ready for use, so jumping in the deep-end! Any advice for me?

I'm made a photosynth of it so feel free to explore.. (Use arrow keys to navigate or select the "overhead" option to get a plan view) exteriror: http://photosynth.net/view.aspx?cid=1e7e06c5-bdca-4fdb-9aed-7da282c15f19
interior: http://photosynth.net/view.aspx?cid=297faa40-d278-426e-950e-1b83e2c10e1d

 

[Feltwell]

Welcome Simon. The photosynth thing is very posh - you've also saved yourself from 10 replies all asking for pictures! Clearly you've got a lot of work on your hands there, but looks a great project - just be aware that "6 months" tends to be flexible!

I know next to nothing about working with cob but others on here do have knowledge and I'm sure will reply later. I just wanted to say how nice it is to see someone working, in a sympathetic manner, on a vernacular Irish building - so often in Ireland the approach in recent years seems to have been to leave the old farmhouse to dereliction and build a "nice new bungalow" next door instead.

 

[Flyfisher]

Welcome indeed. That's quite a project but it looks as if it has wonderful potential. I also loved the Photosynth thingy, which I hadn't seen before. Unfortunately I've no experience of cob either but, as Feltwell said, there are cob owners on here so be patient.

 

[robgil]

Photos please?
Sorry , have to keep up the tradition.

That cement yard, that might be a cause of some of your damp , not letting the ground dry out naturally. Does it have any drainage or does the water flow where it likes?

 

[simon.d]

Thanks for the welcome all and glad ye like the Photosynth..

Photos please?
Sorry , have to keep up the tradition.

That cement yard, that might be a cause of some of your damp , not letting the ground dry out naturally. Does it have any drainage or does the water flow where it likes?

The wall facing the yard is actually bone dry, so I don't think it's causing a problem. But will dig a drain along that face just in case.. It's the back wall that's causing problems possibly as a combination of poor guttering, cement render, removal of eaves, heavy weathering and poor drainage. So each of these issues need to be addressed me thinks.. There also seems to be no real stone plinth / capillary break under the cob wall, only a very rudimentary single layer of stones forming the foundation, so this may also be attributing to the damp.

 

[Schoolmarm]

It won't allow me to access it.

 

[simon.d]

I know next to nothing about working with cob but others on here do have knowledge and I'm sure will reply later. I just wanted to say how nice it is to see someone working, in a sympathetic manner, on a vernacular Irish building - so often in Ireland the approach in recent years seems to have been to leave the old farmhouse to dereliction and build a "nice new bungalow" next door instead.

It's a shame the way vernacular buildings are being treated over here.. I need planning permission to restore this building to habitable standards, but none to demolish it.. Bit of an imbalance there! The first nugget of advice anyone gives me is to bulldoze it and rebuild in concrete, its ingrained in peoples heads, bungalows are the bees knees apparently... Character/History/Heritage doesn't seem to factor in peoples valuation of these properties. It's a sad situation the result being this country is practically devoid of knowledgeable tradespeople/architects/engineers, leaving me more or less on my own. UK Publications and resources like this forum have been my saving grace, answering the multitude of questions that have been thrown in front of me over the course of this project..

It won't allow me to access it.

You need a microsoft plugin called silverlight.. So Mac's and browsers like firefox may cause some issues!

Here's a couple:

 

[Flyfisher]

It won't allow me to access it.

You need a microsoft plugin called silverlight.. So Mac's and browsers like firefox may cause some issues!

It worked OK with firefox on my winXP PC

 

[simon.d]

Finally gotten concrete block chimney down, revealing soot stained, cob wall behind

..

Also found the original hearth underneath, complete with cast iron pipe (bottom left corner) to bring in air from the mechanical bellows:

What the hearth area would have looked like back in the day:

 

[Penners]

Welcome, Simon. That looks like a bit of a project you've got there. I'm glad to see that you made a start on it with some tasteful tiling.

I have no experience of cob or clay lump buildings, but I understand that their greatest enemy is damp. I'm sure you recognise that the concrete skin on your problem wall is very likely to be at best an exacerbation of its dampness and at worst the root cause. But I suspect you're going to have to be pretty careful taking the concrete off, until you're sure that the wall underneath still has the capacity to support itself and the structure.

As regards the possible source of the damp, I can't quite work out which "back" wall you mean, but is it one of the gable ends? If so, then - noting that the building stands on a slope - I wonder whether a contributory cause might be an accumulation of surface water, either where its downhill flow is interrupted by the uphill gable wall, or where it is accumulating at the downhill end.

One other thought - are the ground levels outside above or below the interior floor level? If exterior ground levels have been allowed to rise, this could also exacerbate the damp.

However, I'm sure your description of a minimal masonry plinth will also be a strong contribution to the problem.

 

[simon.d]

Thanks Penners.. Surface water could well be contributing factor, and so could the levels.. I have yet to do any work outside the house, as was waiting for some good weather before I go stripping off the external renders. I have a feeling that the foundation plinth (as small as it is) may well be submerged outside, so will need to investigate that further..

When I say "back wall", I'm referring to the wall on the long side of the house opposite the front door.. And the damp seems to be worst towards the centre of the building so away from the gables. I think it's down to a multitude of factors so I taking a good few steps to address it.. 1. Deep drains all along the exterior perimeter of the house. 2. Removal of cement cladding/floors. 3., Restoration of thatch roof with large overhang for eaves.

 

[Penners]

taking a good few steps to address it.. 1. Deep drains all along the exterior perimeter of the house. 2. Removal of cement cladding/floors. 3., Restoration of thatch roof with large overhang for eaves.

Those all sound good moves, Simon. I'm sure you know this, but do take care digging deep trenches around the outside, against the walls. You absolutely must not dig below the depth of the masonry plinth.