Can spray foam be used to seal a old stone wall before slabbing.

Robbieg007

Hi all
I currently am in the process of getting plans drawn up for a cottage restoration, The wall on the side of the house seems to have a bit of water penetration, no mold just paint keeps peeling off, I was wondering if spray foam could be sprayed on to the wall to prevent water penetration and then slab over the spray foam, I would fix metal studding to the wall before having them spray foamed in between. Sort of like walltite

Calahonda52

Is there a DPC in the floor and walls?
How old is the cottage?
What is the makeup of the wall?
is there any lime used?
what is the current internal wall finish that is painted?
what is the outside finish?

Robbieg007

No there is no DPC in floors and walls.
I think the House is over 100 years old.
The walls are Lime stone walls with filling in the middle.
Not sure about the lime probably os lime mortor. Not really sure. The external is pebble dash.
Think the internal wall is skimmed and painted.

Calahonda52

Thanks.
The issue here is if the skim is gypsum based as opposed to lime based, then wall is unbreathable.
The foam will be a disaster.

http://www.josephlittlearchitects.com/articles
will get you started.
To do a proper job, the gypsum needs to come off.
Research Calsitherm board or similar
https://www.ecologicalbuildingsystems.com/Ireland/Products/Product-Detail/Calstherm-Board

Robbieg007

Thanks

Just wondering how would i go about slabbing to insulate the walls. Using mrtal stud with rock woor and them slabs.
Are they finished sith lime plaster and painted. Or how are they finished

Calahonda52

Robbieg007 wrote: »

Thanks

Just wondering how would i go about slabbing to insulate the walls. Using mrtal stud with rock woor and them slabs.
Are they finished sith lime plaster and painted. Or how are they finished

The setup has to be breathable all the way through so look at the website i sent you and get your head around the concept of 100% breathability/water vapour permeability.
Slabs/rock wool wrong answer
What stage is the work at?

Robbieg007

Just planning part just trying to figure out what to do and how to do it

TomEire

Im currently fixing up a old house as well limestone walls as well what we did inside was strip back to stone itself clean out joints and point the stone, plastered the walls sand cement lime to let the walls breathe we then used insulated slabs to finish ,the problem is with with a sand and cement finish is the walls could weep.

Calahonda52

Robbieg007 wrote: »

Just planning part just trying to figure out what to do and how to do it

Well you have to be able to deal with the moisture in the floor and walls.
Have you properly functioning french drains outside around the perimeter?
- they help/don't solve.
How high is the water table around the house: e.g. are u on a hill or in a hollow?
For walls facing south/west, solar drive can be an issue as well.
If the house is gutted, consider MHRV as a means of dealing with the airborne moisture vapour.
If you are in a location prone to high humidity in summer, then you may need to consider a chilling coil on the intake to drop the humidity. This would also allow you control the humidity all year round in the house.

TomEire wrote: »

Im currently fixing up a old house as well limestone walls as well what we did inside was strip back to stone itself clean out joints and point the stone, plastered the walls sand cement lime to let the walls breathe we then used insulated slabs to finish ,the problem is with with a sand and cement finish is the walls could weep.

the insulated slabs do not allow the walls to breath.

Robbieg007

TomEire wrote:

Im currently fixing up a old house as well limestone walls as well what we did inside was strip back to stone itself clean out joints and point the stone, plastered the walls sand cement lime to let the walls breathe we then used insulated slabs to finish ,the problem is with with a sand and cement finish is the walls could weep.

Was it hard to strip back to bare walls. How did u fix the slabs

Lumen

Calahonda's advice is good. If in doubt get an arch tech to specify the wall build up. It's really easy to get this wrong because many commonly available building materials used in block built modern houses are unsuitable for a traditional building.

Calahonda52

Robbieg007 wrote: »

Was it hard to strip back to bare walls. How did u fix the slabs

Not the right approach.

Lumen wrote: »

Calahonda's advice is good. If in doubt get an arch tech to specify the wall build up. It's really easy to get this wrong because many commonly available building materials used in block built modern houses are unsuitable for a traditional building.

Thank you for stating it clearly

_Brian

Old stone walls breathe moisture in and out.

If you apply a non breathable aspect inside, the moisture will come in through the stone and get trapped behind the non breathable layer. This will cause damp and mould and become a disaster over time.

BarryD2

Original part of our house is oldish, granite stone with lime mortar, pebble dash render exterior, sand/ cement interior. The previous owners had at some stage dry lined one wall, which I ripped out as it had rotted. We had a chemical DPC injected by a commercial company, we don't have any rising damp but since I don't know if there was before I can't comment on it's effectiveness. Over time, I've added another layer of render with a nap finish over the pebble dash on the exterior. Interior wise, fixed plasterboard with bonding plaster to old walls and skimmed. Seems to be fine on the whole, a little mould growth will occur at one or two spots but this is a function of cooler walls (no insulation) and condensation, particularly say where steam from kettle rises.

Robbieg007

Calahonda52 wrote:

Well you have to be able to deal with the moisture in the floor and walls. Have you properly functioning french drains outside around the perimeter? - they help/don't solve. How high is the water table around the house: e.g. are u on a hill or in a hollow? For walls facing south/west, solar drive can be an issue as well. If the house is gutted, consider MHRV as a means of dealing with the airborne moisture vapour. If you are in a location prone to high humidity in summer, then you may need to consider a chilling coil on the intake to drop the humidity. This would also allow you control the humidity all year round in the house.

The french drains might help a bit.
The land around me is flat land.
I plan on putting in the MHRV

Calahonda52

Robbieg007 wrote: »

The french drains might help a bit.
The land around me is flat land.
I plan on putting in the MHRV

Well if you do then do the walls properly.
In passing, are you digging out the floor and putting in a insulated slab with DPC?

Lumen

BarryD2 wrote: »

Seems to be fine on the whole, a little mould growth will occur at one or two spots but this is a function of cooler walls (no insulation) and condensation, particularly say where steam from kettle rises.

Walls are always cold, the only variation is which bit is cold.

If you insulate the internal face of an external wall, that face (behind the insulation) will get colder. And if there's any way for warm moist air to get to that cold face, it will condense and provide perfect conditions for mould growth. You just won't see it.

(I'm sure you know this already, I'm just stating the obvious)

BarryD2

Well, as mentioned I've put no insulation on these old walls and so as long as house is heated during the winter, they are fine. Being thick, they absorb a bit of heat but also store same and help keep temp even. If we're away for a few days in winter, then an issue arises as it takes a day or two to get the house back to norm. Sure, we're losing a little energy slowly but the small additional cost is way less that external insulation solutions. Weren't keen on interior insulation as rooms small enough. However if OP is out every day or regularly and just wants to come home in the evening and put the heat on, then a solution that heats up quickly maybe better. I think IMHO that older houses with solid walls are better suited to 'traditional living' where buildings are occupied more or less continuously.

TomEire

Calahonda52 wrote: »

Well you have to be able to deal with the moisture in the floor and walls.
Have you properly functioning french drains outside around the perimeter?
- they help/don't solve.
How high is the water table around the house: e.g. are u on a hill or in a hollow?
For walls facing south/west, solar drive can be an issue as well.
If the house is gutted, consider MHRV as a means of dealing with the airborne moisture vapour.
If you are in a location prone to high humidity in summer, then you may need to consider a chilling coil on the intake to drop the humidity. This would also allow you control the humidity all year round in the house.



the insulated slabs do not allow the walls to breath.

Yes i know

Calahonda52

TomEire wrote: »

Yes i know

My reposes was to the OP, not anyone else

TomEire

Robbieg007 wrote: »

Was it hard to strip back to bare walls. How did u fix the slabs

I think it was old lime plaster on walls it came off easy enough mostly in lumps slowest was cleaning out the joints.fix slabs using mushroom fixings drilled into stone wall.walls had 3 coats of plaster to straightening them

Robbieg007

Thanks for the advice guys