DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Building & Construction (http://www.diychatroom.com/f19/)
-   -   12-10-2010 - [s] - question regarding dry-lining stone wall house.jpg (http://www.diychatroom.com/f19/12-10-2010-s-question-regarding-dry-lining-stone-wall-house-jpg-68879/)

peakpilgrim 04-12-2010 09:45 AM

12-10-2010 - [s] - question regarding dry-lining stone wall house.jpg
 
Hi all I have just started posting here. I am living in a very old rendered stone house with no damp-course. I intend to gut each room, dry-line, and put in a concrete floor. Having spoken to a few people I have come up with a preliminary design for doing this which is below.

http://yfrog.com/ao12102010dryliningstonewj

The above is far from complete and I would appreciate any constructive comments.

ccarlisle 04-12-2010 12:08 PM

The problem with this arrangement is that you are using moisture-sensitive building materials in an area where moisture is heading. Your stone wall, in spite - or perhaps because - it is 2' thick dries towards the inside of your home, the moisture coming from the rain, from the ground and from the floor. It moves towards the inside of your home because the inside is drier and warmer... you've made it that way and it's a law of physics.

So moisture is heading into your home, from the walls. The first thing this moisture will meet are the wooden wall studs. These wil conduct moisture further inwards till it meet the next object: the foam. Foam board -the extruded one not the expanded one - will partially let the moisture through but any remaining mositure will condense.

Then it goes through the foam on its way inward and hits the plasterboard having gone around the DPC. More problems.

Now during the winter, the inside pressure of your home causes water vapour from warm to cold so it goes through the plasterboard, through the foam and hits the cold wall where it condenses and causes mould on the stone wall.

Look, from here I don't pretend to have all the answers for you over there - but we face the same laws of physics as you do and that's they way we see things. The solution is not to use water-sensitive materials against the stone wall; put the foam directly onto the stone and build your wall inside of that. Or use a spray-foam, closed cell, and solve the problem permanently. That, tho' is not a DIY project.

The questions I encourage you to ask a builder is for them to give their opinions on where the moisture dries to, inwards or outwards, and listen to their suggestions. Then get back to us...

Just so we're sure on the terminology, "DPC" stands for what exactly. And putting DPC to about 5' from the floor does what exactly? Is that the height of the ground outside?

peakpilgrim 04-12-2010 01:04 PM

Quote:

Originally Posted by ccarlisle (Post 427590)
The problem with this arrangement is that you are using moisture-sensitive building materials in an area where moisture is heading. Your stone wall, in spite - or perhaps because - it is 2' thick dries towards the inside of your home, the moisture coming from the rain, from the ground and from the floor. It moves towards the inside of your home because the inside is drier and warmer... you've made it that way and it's a law of physics.

So moisture is heading into your home, from the walls. The first thing this moisture will meet are the wooden wall studs. These wil conduct moisture further inwards till it meet the next object: the foam. Foam board -the extruded one not the expanded one - will partially let the moisture through but any remaining mositure will condense.

Then it goes through the foam on its way inward and hits the plasterboard having gone around the DPC. More problems.

Now during the winter, the inside pressure of your home causes water vapour from warm to cold so it goes through the plasterboard, through the foam and hits the cold wall where it condenses and causes mould on the stone wall.

Look, from here I don't pretend to have all the answers for you over there - but we face the same laws of physics as you do and that's they way we see things. The solution is not to use water-sensitive materials against the stone wall; put the foam directly onto the stone and build your wall inside of that. Or use a spray-foam, closed cell, and solve the problem permanently. That, tho' is not a DIY project.

The questions I encourage you to ask a builder is for them to give their opinions on where the moisture dries to, inwards or outwards, and listen to their suggestions. Then get back to us...

Just so we're sure on the terminology, "DPC" stands for what exactly. And putting DPC to about 5' from the floor does what exactly? Is that the height of the ground outside?

Hi CC

Thanks for your thoughts on this.

DPC stands for 'Damp Proof Course' [ Actually this should be DPM - 'Damp Proof Membrane']The idea of turning this up the wall 5' is to counteract any rising damp which will, I am told, not rise more than 4' above ground level. [ assume external ground level is roughly 6" below screed level]

The proposed space behind the insulation and plasterboard is double battened with treated timber and vented to the outside to counteract the problem of condensation in the enclosed cavity.This space, as you say, will get damp.

I wonder if I included a vapour barrier, also, between the battens and insulation, if this would improve things?

If I put the foam directly against the outside wall I think I would still need some sort of a cavity area?

ccarlisle 04-12-2010 01:53 PM

Ah-ha...well, see, I overlooked that grill that vents the wall to the outside and that changes a bit of things for me. Obviously you have a milder climate than we do (we would not have that grill here) but still that has me scratching my head.

So, your system may be fine for your area; here. we don't put a vapour barrier everywhere and wouldn't in your situation - if it were here. But I think I might just have to give way to your local guys, as having a direct-vented wall to the outside really has me wondering. And yes, if the area behind the foam is to be vented, then leave a space te way you have done, for proper air circulation.

I need a break. I should look into making one of my famous 'house calls' to your part of the world!

stuart45 04-12-2010 04:03 PM

Have you considered using something like Kingspan K18, which has insulation and a vapour barrier in it.
The problem with taking the DPM up the wall is that any water vapour penetrating through the plaster board may condense and run down into the screed as the DPM is on the cold side of the insulation.

peakpilgrim 04-12-2010 04:45 PM

Quote:

Originally Posted by stuart45 (Post 427724)
Have you considered using something like Kingspan K18, which has insulation and a vapour barrier in it.
The problem with taking the DPM up the wall is that any water vapour penetrating through the plaster board may condense and run down into the screed as the DPM is on the cold side of the insulation.

Hi Stuart

Thanks for you thoughts on this.

The idea of a combined insulation and vapour barrier sounds good. I am assuming the vapour barrier is at the room side of the insulation which solves the problem regarding the DPM which you raise.

If that is the case I could probably cut the DPM 6"" above the screed and allow the inbuilt vapour barrier to stop any moisture problem

stuart45 04-12-2010 04:58 PM

The VP is on the warm side of the insulation.
Are you dry lining because of a damp problem or for better insulation? Or both.
Many damp problems in old building are often misdiagnosed as rising damp when in fact they are caused by condensation.

peakpilgrim 04-12-2010 05:17 PM

Quote:

Originally Posted by stuart45 (Post 427749)
The VP is on the warm side of the insulation.
Are you dry lining because of a damp problem or for better insulation? Or both.
Many damp problems in old building are often misdiagnosed as rising damp when in fact they are caused by condensation.

Hi Stuart

I am drylining for both insulation and damp-proofing. I want to get a catch all
system which will solve all the problems.

I live in a very damp area and have to use dehumidifiers to make the rooms usable. The walls are solid and have no damp course.

ccarlisle 04-12-2010 07:10 PM

The more I think about this, the more I think you're heading for problems. The way I see it is that your house was built with the foundation walls the way they are for good reason: they were meant to dry to the inside without anything likeplasterboard on them. So they were intended to get wet and dry by the circulation of air on both sides - especially the inside because of evaporation. The grill may not be enough if you cover the walls....

Now prevent air circulation from happening and you risk ruining your foundation...I would even increase the amount of space between the stone and the plasterboard to 6 inches or more.

:huh:

peakpilgrim 04-13-2010 02:28 PM

Quote:

Originally Posted by ccarlisle (Post 427828)
The more I think about this, the more I think you're heading for problems. The way I see it is that your house was built with the foundation walls the way they are for good reason: they were meant to dry to the inside without anything likeplasterboard on them. So they were intended to get wet and dry by the circulation of air on both sides - especially the inside because of evaporation. The grill may not be enough if you cover the walls....

Now prevent air circulation from happening and you risk ruining your foundation...I would even increase the amount of space between the stone and the plasterboard to 6 inches or more.

:huh:

Hi CC

You may well be right in what you say. This house was built in the 'old style' where the rooms were meant to be kept relatively clear and the walls allowed to 'breathe' with plenty ventilation, no central heating, only an open fire; whereas now each room is jam-packed with all sorts of junk.

The proposal was to vent the gap behind the stud by core-drilling a 3" hole every 3m [ approx. 10'] and slapping a grill over the hole; this may not be enough, as you say, but rather than lose more room inside by increasing the cavity I think I would rather drill more holes. I could increase the cavity slightly by using larger battens but 6", with the insulation, would really start to cut down the room sizes I think. I could,also open the area into the roof space, which is well vented, as the house is a bungalow.

ccarlisle 04-14-2010 10:42 AM

Essentially, what you're doing is creating 'weep holes' at the bottom of the stone wall, much like we do when we create brick walls.

Brick walls here are meant to get wet and then dry without letting the moisture inside the house and therefore we purposely leave small gaps at the base of the wall to let cold air in. This cold air eventually gets warmer and rises creating a chimney effect and thus air movement...

slickgt1 04-14-2010 12:38 PM

I don't know if I would do this, but I am in NYC. I would deff do expandable closed cell insulation in between 1" metal studs, placed 1" from the wall. This is a water barrier also, the studs are there to help you trim it, and follow a proper line for the insulation. This would give you about 2" of insulation, even if it does get wet, it does not collapse, and won't let the water pass to the inside. Then I would do another course of 1" metal studs, this time with no insulation, this is just for your wiring, and something to attach your sheetrock to without puncturing the insulation, while creating an air gap between the insulation and sheetrock. I would go with the green board too just to increase protection. I would keep it about half inch off the floor and half from the ceiling. This will let your wall breathe. You can cover the gaps with some fancy carpentry work, crown moldings and base moldings.

Consider radiant floor heat as well. Electric or water, especially since you plan on concrete floor.

I am not sure that your current plan would work, but like ccarlisle stated, you might have to leave all this in the hands of your contractors locally. That vent might actually pull moisture in there since no matter what it will be warmer in the wall then the outside. I try to stay away from puncturing walls as much as possible. You will also need a ton of detail work to make sure that vent does not cause a draft, and pull air from the house. Everything will need to be sealed tight, or you might be heating and cooling the neighborhood.

peakpilgrim 04-14-2010 06:48 PM

Quote:

Originally Posted by ccarlisle (Post 428620)
Essentially, what you're doing is creating 'weep holes' at the bottom of the stone wall, much like we do when we create brick walls.

Brick walls here are meant to get wet and then dry without letting the moisture inside the house and therefore we purposely leave small gaps at the base of the wall to let cold air in. This cold air eventually gets warmer and rises creating a chimney effect and thus air movement...

Hi CC The trick would be to get just enough air movement to remove excess moisture from between the stud and existing wall.

peakpilgrim 04-14-2010 06:50 PM

Quote:

Originally Posted by slickgt1 (Post 428658)
I don't know if I would do this, but I am in NYC. I would deff do expandable closed cell insulation in between 1" metal studs, placed 1" from the wall. This is a water barrier also, the studs are there to help you trim it, and follow a proper line for the insulation. This would give you about 2" of insulation, even if it does get wet, it does not collapse, and won't let the water pass to the inside. Then I would do another course of 1" metal studs, this time with no insulation, this is just for your wiring, and something to attach your sheetrock to without puncturing the insulation, while creating an air gap between the insulation and sheetrock. I would go with the green board too just to increase protection. I would keep it about half inch off the floor and half from the ceiling. This will let your wall breathe. You can cover the gaps with some fancy carpentry work, crown moldings and base moldings.

Consider radiant floor heat as well. Electric or water, especially since you plan on concrete floor.

I am not sure that your current plan would work, but like ccarlisle stated, you might have to leave all this in the hands of your contractors locally. That vent might actually pull moisture in there since no matter what it will be warmer in the wall then the outside. I try to stay away from puncturing walls as much as possible. You will also need a ton of detail work to make sure that vent does not cause a draft, and pull air from the house. Everything will need to be sealed tight, or you might be heating and cooling the neighborhood.

Hi Slick Thanks for your contribution. Good point about the services and floor heating which gives further food for thought

ccarlisle 04-15-2010 06:45 AM

Quote:

Originally Posted by peakpilgrim (Post 428796)
Hi CC The trick would be to get just enough air movement to remove excess moisture from between the stud and existing wall.

Yes, we agree there! Over here, buildings that are over 100 years old are antiques and need special treatment to counter the #1 enemy we both have: moisture. On top of that we have extreme temperature shifts (+28 deg C in summer and -18 deg C in winter, with about 2-3 feet of snow for 4 months of the year) that perhaps you don't.

So we have specialized restoration firms that handle this sort of problem - because it is not just a case of dry-lining an old wall...moisture flow must be handled with the building's overall health in mind.

I admit to being guilty of not doing that earlier; but I now know that you're on the right track increasing the ventilation on the walls surface to promote drying - which in turn will promote a decrease in mould.

I am not fully happy with the spray-foam idea; I still need to think that one through. We promote foam usage heavily but here we might not have the right circumstances.


All times are GMT -5. The time now is 05:48 AM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved