Old Victorian House Dry-Line

TiNcAn

I have an old victorian red brick (pebbled dashed!) house which has no DPC and concrete floors downstairs.

The original plaster is now literally falling off the walls so I have striped them back to the brick.
After much reading, I am considering to go a similar approach as described in this blog.
http://jack-kelly.com/insulating_our_victorian_living_room

My plan would be to metal dry-lining system that allows for an air cavity of ~25mm. Additional air bricks would be added to aid the circulation of air in the caivty with the outside to remove trapped moisture. 
On top of the dry-lining system I would add 50mm rigid insulation, vapour barrier and finally plasterboard. This should prevent any warm air from coming in contact with the cold air and condense somewhere inside the wall. And any damp rising up would be allow to evaporate and exit through the air bricks.

Other approaches I have read for old brick walls would be to use a lime plaster and some breathable insulation (sheeps wool).

I think the dry-lined approach would be significantly easier, and less costlier. I would like to others opinion and whether they would have any suggestions or experience doing this.

The exterior pebble dash is also something which I think needs to come off since it is probably trapping moisture in the bricks.

listermint

Why not external insulation. I assume your rooms are already quite small and will be significantly smaller with your plans

TiNcAn

I don't believe external insulation would be suitable because it would trap moisture in the brick and not allow it evaporate to outside.

Calahonda52

TiNcAn wrote: »

The exterior pebble dash is also something which I think needs to come off since it is probably trapping moisture in the bricks.

Yes, its pretty impervious..
Had a quick flash down through the blog and it seems he is not aware of the fire regs associated with such stand off dry lining.

I suggest you look here
http://www.ecologicalbuildingsystems.com/Ireland
at solutions that will cover your situation.

eg
https://www.ecologicalbuildingsystems.com/Ireland/Products/Product-Detail/Calstherm-Board

lots here also

http://www.josephlittlearchitects.com/articles

Dont Be at It

Calahonda52 wrote: »

Yes, its pretty impervious..

Why would external render need to be removed?
Would this not be helping to prevent moisture from the elements getting into the brick?

mad m

Dont Be at It wrote: »

Why would external render need to be removed?
Would this not be helping to prevent moisture from the elements getting into the brick?

Probably due to the fact there is no DPC in house?

TiNcAn

mad m wrote: »

Dont Be at It wrote: »

Why would external render need to be removed?
Would this not be helping to prevent moisture from the elements getting into the brick?

Probably due to the fact there is no DPC in house?

Yes that is my thinking. The damp from the ground is traveling up the bricks and unable to exit through the external wall since not very permeable. This leaves the water in the bricks only one place to go and that is the internal walls.
Calahonda52
In general, what would need to be done to become more compliant with the fire regulations.
The links you gave are also quite interesting. I will try to get my head around them and see what is the best approach.

On a similar point, when using sheeps wool for dry-lining, are the studwork right up against the wall? And how to you avoid the issue of thermal bridging with the studwork?

M.T.D

If I had rising damp the first thing I would be doing is fixing that or at least doing everything possible to reduce it.
There are many options to achieve this, all of which I would try before putting a wet surface behind a stud.

TiNcAn

M.T.D wrote: »

If I had rising damp the first thing I would be doing is fixing that or at least doing everything possible to reduce it.
There are many options to achieve this, all of which I would try before putting a wet surface behind a stud.

You are completely right. I noticed that the gutter is over spilling onto the wall and am getting this corrected asap. This will go a long way to removing moisture continually entering the bricks.
The next options I am not so sure about. The methods I know about are:

• DPC chemical injection into mortar
• Electro Osmotic
• Tanking

 I am unsure which approach would be better for a period property. I don't think using a DPC chemical injection is the right approach as it will only serve to prevent the moisture from rising past a certain course of the bricks. A tanking layer would also only serve to prevent the moisture from exiting the brick where it has been applied but not actually stopping it from entering the brick. 
Right now the Electro Osmotic seems the least intrusive but I need to research this more. Any ideas?

And as I mentioned before, the pebble dash is surely not helping the bricks evaporate the moisture so this is another measure that could help deal with the damp.

M.T.D

I is a long time since I installed a dpc in an old house.
We used a combination of approaches.
First was to dig out all around the house, down to foundation level to reduce water transfer from the outside ground added drainage and back filled with stone, concrete cap to steer water away from wall. If I was redoing now the I would add insulation.
We used the high pressure injection system into the bricks, they were good quality red brick and we had very few problems with split bricks.
They were a pig to drill as the damp dust clogged the drills.
It was a timber floor with many of the joists needing replaced but at least the subfloor was reasonably dry
Old plaster was removed on lower half of the wall
The wall was waterproofed and then rendered

I see there are now creams to inject between the bricks and plastic sheets that can be fastened to the wall and rendered over

Does your concrete floor have a dpc, insulation etc. On one house I worked on the rising damp was from a leaking pipe under the concrete floor of the adjoining house only found out when we dug a hole in the subfloor and it filled up with water

Calahonda52

Fire regs
http://www.housing.gov.ie/sites/default/files/publications/files/technical_guidance_document_b_fire_safety_volume_2_dwelling_houses.pdf
extract
Internal fire spread (structure).
B8
3) A dwelling house shall be so designed and constructed that the unseen spread of fire and smoke within concealed spaces in its
structure or fabric is inhibited where necessary.

Normally done by having a solid full depth horizontal batten top and bottom of the dry lining in each room

PS this is NOT advice

PS eile: of course if house is more than two storeys, then the regs require a lot more

http://www.housing.gov.ie/search/archived/current/category/housing/type/publications?query=loft%20conversion

TiNcAn

M.T.D wrote: »

I is a long time since I installed a dpc in an old house.
We used a combination of approaches.
First was to dig out all around the house, down to foundation level to reduce water transfer from the outside ground added drainage and back filled with stone, concrete cap to steer water away from wall. If I was redoing now the I would add insulation.
We used the high pressure injection system into the bricks, they were good quality red brick and we had very few problems with split bricks.
They were a pig to drill as the damp dust clogged the drills.
It was a timber floor with many of the joists needing replaced but at least the subfloor was reasonably dry
Old plaster was removed on lower half of the wall
The wall was waterproofed and then rendered

I see there are now creams to inject between the bricks and plastic sheets that can be fastened to the wall and rendered over

Does your concrete floor have a dpc, insulation etc. On one house I worked on the rising damp was from a leaking pipe under the concrete floor of the adjoining house only found out when we dug a hole in the subfloor and it filled up with water

The house most likely does not have much or granite slabs for foundations. The front of the house is also facing directly onto the street. I presume this would mean that any DPC installed would only be possible from the inside so the damp would still get into the bricks.
In that there was holes in the wall downstairs were joists were originally placed, so it would have had a wooden floor. But was removed a number of years ago and they poured concrete downstairs instead, most likely without any DPC.

I am also very cautious about injecting anything into the brick, as this only prevents the damp rising past a certain level and the bricks below would be forever damp. The bricks below the injection layer may also suffer as a result of the increased level of moisture. To be honest, I don't think the concrete floor is the major issue with regards to the damp and is primarily the ground walls where the issue is present.

Do you have any experience with the other DPC systems?

M.T.D

In any house the bricks below the dpc will be damp. The whole point of a dpc any type, plastic, tar, injection, electrical is that the damp/wet stays below the dpc.
To work effectively the outside ground needs to be below the dpc, and the inside floor usually above the dpc.
If your concrete has no damp proof layer and is touching the outside walls it will be damp as well. Put a layer of polythene on the floor near a wall with a board or a few bricks on it, check under it after a few days. This will show you any damp.

TiNcAn

That is some sound advice. I will carry out your experiment in a few places to find out where there is damp present. Would a positive result (condensation under polythene sheet) indicate that there is damp coming through the concrete floor?

The internal level of the house is the same as the footpath level outside. So there is no straightforward way to achieve a dpc below the inside floor. Any ideas on how to tackle this without completely tearing the house up?


This is why I come back to my original idea to install a stud wall which stands off from the original wall. This wall is sealed from inside but open to the outside through the air bricks. Obviously there would need to be some reconsideration given to this to take account of the fire regs.