Drylining old house.

Gingernuts31

I'm looking at drylining my old 1940's house. No insulation in the walls of the old part, newer part (whole back of the house) was built early 2000's we think.

There is mould on the plaster and i've been told I have rising damp but im skeptical about that.

I'm looking at stripping the exisitng plaster off the walls all the way to the ceiling to expose the cement/sand finish. Installing a DPM straight onto the wall using plastic fixings with rubber seals around the screws holding it up. Then put up 2x2 battons and installing a vapour barrier insulated plaster board, skim over and job done. Anyone advose me on if this is the correct route to go?

I'll also be looking at a ventilation system to deal with condensation that is building up currently in the house even though its only me here when its very cold outside the windows get soaked.

murph226

Who told you about the rising damp?

You are skeptical about it even though you have problems with condensation?

Gingernuts31

Just because I have issues with condensation it doesn't mean I have rising damp.1 Guy who came to insulate the attic told me it was rising damp and another told us once the attic was insulated it would stop condensation yet we still have it. All the windows end up the same when its cold outside in the old part and newer part of the house. There is no salt deposits on the walls and the only effects is the black staining on the paint and the paint peeling off in some area's not it all, there is no real tide mark as its all over the shop, also I did say the plaster is away from the walls in some places but that issue is not that bad.

Thats why i'm looking at the drylining now more so than getting the walls fixed which prob won't work anyway and then doing the drylining. The only difference is with the DPM at the wall instead off insulating straight off. I know you'll prob say don't cover it up it will only make it worse but as far as i'm concerned if I have the DPM at the wall and sealed up no water can get through to the new insulation.

newmug

Why dont you just put insulated slabs straight onto the walls WITH the plaster on? You could put a vapour barrier behind thaem if you wanted, but there would be no real need, the damp wont come through the insulated slabs.

Poor Uncle Tom

I think the idea is to use the DPM like basement tanking and to then insulate inside this using battening to create a cavity. Insulated slabs will not do a 'tanking' job.

The problem I would find with the DPM method is that the thickness of insulation on the slabs would not be enough on its own.

newmug

Poor Uncle Tom wrote: »

I think the idea is to use the DPM like basement tanking and to then insulate inside this using battening to create a cavity. Insulated slabs will not do a 'tanking' job.

The problem I would find with the DPM method is that the thickness of insulation on the slabs would not be enough on its own.

But why would you need a tanking job and a cavity? Once the water doesn't come through, you're sorted. And with insulated slabs, you're insulating aswell! 2 birds with one stone!

Poor Uncle Tom

But isn't that the point, insulated slabbing is not waterproofing.

Gingernuts31

Poor Uncle Tom wrote: »

The problem I would find with the DPM method is that the thickness of insulation on the slabs would not be enough on its own.

Tom you have the right idea, I want to use the DPM as a tanking job only without the actual tanking so to speak. When you say slabs do you mean the insulation boards? You don't think the DPM would be enough to stop the damp coming through?

Gingernuts31

newmug wrote: »

But why would you need a tanking job and a cavity? Once the water doesn't come through, you're sorted. And with insulated slabs, you're insulating aswell! 2 birds with one stone!

I was thinking of doing that newmug but I perfere the idea of have a DPM up there 1st. I honestly don't know why I'm talking about battons on top of DPM then insulation boards on top of them, I guess I just think its better to have a cavity? Or it doesn't really make any difference just less work with no battons?

Poor Uncle Tom

Gingernuts31 wrote: »

When you say slabs do you mean the insulation boards?

Yes,

Gingernuts31 wrote: »

You don't think the DPM would be enough to stop the damp coming through?

The DPM, if done correctly, will stop the damp coming through, but the DPM must be carried across the floor as well continuing the tanking theme.

There are two problems that I see:
1. detailing at windows and opes.
2. total insulation in the walls, if it is the insulation on the slabbing on its own it wouldn't be enough.

Poor Uncle Tom

Gingernuts31 wrote: »

I honestly don't know why I'm talking about battons on top of DPM then insulation boards on top of them,

I think you might be onto something here, if you use metal stud battens and insulate between them as well as the insulated slab on top.

Gingernuts31

Poor Uncle Tom wrote: »

I think you might be onto something here, if you use metal stud battens and insulate between them as well as the insulated slab on top.

I will have to seek help on the windows as i'll need new window boards so old 1s will have to come out. How far out would the metal battons with insulation between then insulation on top come out into the room do you think? As it is they are somewhat tight for space.

Could I put fibreglass between the metal batons or is has to be boards? Also can vapour barrier boards be fitted onto the metal battons with meal fixings?

Poor Uncle Tom

Very specific questions which should only be answered by someone giving you on-site advice but I will answer you here as best I can.

The metal battens come in varying thicknesses, I would probably use the 48mm ones, but it would depend on your particular circumstances.

If you use the 38mm insulation with slab thats 50mm thick with the 48mm battens thats a total of 98mm on the external walls.

Could I put fibreglass between the metal batons or is has to be boards?

You could put fibreglass between the studs but you would need to allow for 'creep' where the quilt would slip to the end over time and leave no insulation at the top.

Also can vapour barrier boards be fitted onto the metal battons with meal fixings?

Yes.

GreeBo

Id worry about a DPM thats just ending at the floor.
You are going to end up with any moisture hitting the DPM, running down it and pooling on the floor.
Not good.

Gingernuts31

GreeBo wrote: »

Id worry about a DPM thats just ending at the floor.
You are going to end up with any moisture hitting the DPM, running down it and pooling on the floor.
Not good.

True but I don't really have any option. I have 2 wooden suspended floor in 4 of the rooms il be doing too. All i can do in that instance is tuck the DPM in towards the wall away from the floor and let it pool back up at the wall. There doesn't seem to be any wet on the walls though, if there is its very slight, its mostly the windows and the freezing rooms that are the prob. See there was no DPC fitted when this house was built so im stuck no matter what I do.

Gingernuts31

Poor Uncle Tom wrote: »

Very specific questions which should only be answered by someone giving you on-site advice but I will answer you here as best I can.

The metal battens come in varying thicknesses, I would probably use the 48mm ones, but it would depend on your particular circumstances.

If you use the 38mm insulation with slab thats 50mm thick with the 48mm battens thats a total of 98mm on the external walls.

You could put fibreglass between the studs but you would need to allow for 'creep' where the quilt would slip to the end over time and leave no insulation at the top.
Yes.

Thanks for that Tom, you think it can be done regardless of the damp though even if its only slight apart from the paint and mould? Going by what you've said so far you think I could prob go with 100mm of fibreglass between battens & 50mm of board? 6 inchs off the walls? Sorry for being stupid im not the best when it comes to DIY lol.

GreeBo

Gingernuts31 wrote: »

True but I don't really have any option. I have 2 wooden suspended floor in 4 of the rooms il be doing too. All i can do in that instance is tuck the DPM in towards the wall away from the floor and let it pool back up at the wall. There doesn't seem to be any wet on the walls though, if there is its very slight, its mostly the windows and the freezing rooms that are the prob. See there was no DPC fitted when this house was built so im stuck no matter what I do.

Well I wouldnt use "no option" as a good reason to make something potentially much worse. You dont want to rot your joists out.

Also I dont really think you should be putting a DPM onto a wall.
DPM is to stop dampness rising up the wall/floor and into the living space.

You need to identify the source of this condensation, condensation and damp are kinda different things. If you have rising damp then on an old house probably a chemical DPC is the most cost effective way of doing it.
Is there an existing DPC? If there is, it it high enough? It should be a foot or so above external ground level.
Check for leaks in the roof or gutter, a small gutter leak can lead to dampness in the corner of a house, especially an old one.

If you have old, wet plastered walls then they wont really get wet, just damp as they can absorb a lot. If you windows are soaked and its just you then you definitely have damp in the house.

Bottom line, identify the true source and then go from there. You could be making a lot of heartache and expense for yourself, only to be (literally) cover up the problem for a few months.

Gingernuts31

GreeBo wrote: »

"You need to identify the source of this condensation, condensation and damp are kinda different things."

No ventilation in the front of the house which is about 60% of the overall area.


"If you have rising damp then on an old house probably a chemical DPC is the most cost effective way of doing it."

Olny thing the might work on my walls is the EO but the chemical injection stuff is a no go as I have solid concrete walls/mass concrete as far as I know.


"Is there an existing DPC? If there is, it it high enough? It should be a foot or so above external ground level."

Can't tell if there is or not, I doubt it.


"Check for leaks in the roof or gutter, a small gutter leak can lead to dampness in the corner of a house, especially an old one."

Tops of walls are fine it just the bottom area.



"If you have old, wet plastered walls then they wont really get wet, just damp as they can absorb a lot. If you windows are soaked and its just you then you definitely have damp in the house."

Previous owners plastered over the walls to sell the house thus hiding the damp and it came back in winter of that year. This was in 2006. But the windows in my bedroom also get wet the same way and that part was only built early 2000's so would have a DPC. So windows in rooms with no DPC and insulation look the same way as rooms with insulation and DPC. Hence why I think no rising damp just condensation.



Bottom line, identify the true source and then go from there. You could be making a lot of heartache and expense for yourself, only to be (literally) cover up the problem for a few months.

I understand that but the issue I have is that if the only thing that will work on the walls is EO then im screwed because I plan on leaving the country next year for good but would like house sorted before goingas to maybe rent it out and am not leaving the electric on just for EO while house is empty as it could be for a long time cause it's in a crap town where nearest ATM is 15 mins drive away.

Gingernuts31

Sorry for re-opening this thread.

1/ I've decided to go with the chemical injection with holes at every 6 inches apart so the chemical only has to travel 3 inches either side to meet up with next hole.

2/ going to tank over the mass concrete wall to a height of 1.5 meter to make double sure no rising damp gets through the walls

3/ Fix 2x1 wooden battens to the wall to support insulated plasterboard.

4/ insulate the rooms with either kingspan k18, tw52 or xtratherm (open to suggestions about which of these is the best and cost effective, I know it won't be easy to get both in same board)

5/ seal up joints with tape and plaster over, paint and job done.

I was thinking of a PIV system to ventilate the house but thats not possible as can't get any type of ventilation that runs off elec for reasons I don't really want to say and it's not cause of the cost . I was thinking of just knocking holes in each of the walls and put putting up normal vents that screw into the wall and leaving the hole (no tube so to speak) there to ventilate around the timber battens too. Anyone see an issue with this?

My father who is a carpenter is going to help me do all the work but I'll also be looking for a quote for the drylining so as to get the grant from the SEAI.

Any help greatly appreciated as hoping to get started in Jan.

GreeBo

How are you going to securely fix the battens without penetrating your tanking?
You might as well just mushroom fix the insulated board straight to the wall.
How true is the wall? Another, probably better, option would be to build a stud wall just away from your existing wall, thus ensuring you are not going to breach your tanking (though if you have a chemical barrier you shouldnt need the tanking anyway)

If your dad is a carpenter then you should be able to knock up a stud frame quicker than you would be shimming out old, uneven walls anyway.

Gingernuts31

I hadn't really thought about fixing the battens without penetrating the tanking. Your right a timber frame would make more sense. The tanking is just to make sure no damp comes through as I'm not certain the chemical injection will work 100%. I know you could argue why bother with it then but there is nothing else I can do. If I go without chemical injection and just do tanking then the water will just be stuck in the wall. Does the list make sense to you? All going well of course? Also any idea what is the best insulated plasterboard with vapour barrier that doesn't cost the same as Kingspan k18 but more or less has the same thermal properties in your opinion?

GreeBo

If the problem is "just" rising damp then you dont need tanking, the chemical DPC will stop the damp, however you need to know what you are doing when injecting the DPC.
Where are you planning on injecting it? What level and into what?
Are the floors solid? How were the walls constructed? Cavity, solid etc?

Gingernuts31

GreeBo wrote: »

If the problem is "just" rising damp then you dont need tanking, the chemical DPC will stop the damp, however you need to know what you are doing when injecting the DPC.
Where are you planning on injecting it? What level and into what?
Are the floors solid? How were the walls constructed? Cavity, solid etc?

There are 4 rooms that are getting done. The floor is higher than the footpath outside around the house. For the 2 rooms that have wooden suspended floors it will be injected in the concrete below the wooden beam that supports the floors, however I have an issue with this as it won't be 6 inchs above the outside footpath if it's done that way. I'd perfere to injected behind skirtboard and just treated the wooden support for floor, is this do-able? Then the other 2 rooms are just concete floors so wil be injecting behind skirting boards. Walls seem to be mass solid concrete as it was built in 1940s and covered over with sand cement mix then just plastered over that hence the drylining.

GreeBo

The chemical DPC has to form a complete layer otherwise it wont work, so you need to know the depth of the wall and also its content. If the wall has "fill" in the middle then you may need a specific chemical.

tbh I think you would be suited to get an expert in for this part, save the money doing the chippie work where you know what you are at. It would be a disaster to do all this and then have to redo it due to mistakes in the beginning.

Gingernuts31

Mass solid concrete, man next store used to live in this house for 35 years before his son bought it off him. walls seem to be 9 inchs thick. Can't really measure properly, only at front door. I did say i'm not 100 on the chemical DPC. Damp stoere in dublin told me they could do it but they'll just as easily sell me the same stuff they use to do it myself. it's not hard to do and my father is no idiot when it comes to DIY.

GreeBo

Gingernuts31 wrote: »

Mass solid concrete, man next store used to live in this house for 35 years before his son bought it off him. walls seem to be 9 inchs thick. Can't really measure properly, only at front door. I did say i'm not 100 on the chemical DPC. Damp stoere in dublin told me they could do it but they'll just as easily sell me the same stuff they use to do it myself. it's not hard to do and my father is no idiot when it comes to DIY.

Nothing is "hard" to do and you dont need to be an idiot to do something incorrectly out of ignorance.

Gingernuts31

GreeBo wrote: »

Nothing is "hard" to do and you dont need to be an idiot to do something incorrectly out of ignorance.

I understand but I do think it will be done correctly. I'm not that worried about it working 100%. I know some say yes chemical DPC will work in all masonry and then other say it won't. I asked Damp Store would it work in my walls and sure enough they said yes, I did ask the manufactures would it work in my walls but they never came back to me. Hence why i'm not 100% on it as they will tell u everything works cause they're selling it. Even if it doesn't work 100% still better than just doing the tanking and leaving water sitting in the wall with nowhere to go?

GreeBo

Gingernuts31 wrote: »

Even if it doesn't work 100% still better than just doing the tanking and leaving water sitting in the wall with nowhere to go?

if it doesn't work 100% then you are back where you started

except this time you spent a bunch of cash and have also ruined a nice finished wall..

Gingernuts31

What do you suggest? Just do DPC and leave tanking or vice a versa? Or still do both but get DPC injection done professionally?

GreeBo

Get a professional in to determine what problems there are and take the appropriate remedies.
Then you can fit out to your hearts content knowing you dont have to worry about moisture issues.

Gingernuts31

GreeBo wrote: »

Get a professional in to determine what problems there are and take the appropriate remedies.
Then you can fit out to your hearts content knowing you dont have to worry about moisture issues.

Already did 2 of them. 1st said it was just condensation cause attic wasn't insulated and once that was done it'd be fine. Attic got insulated and walls aren't fine. Got another guy in and he said it's rising damp and poor ventilation. Only 2nd guy wanted to use Electro Osmosis on it cause he said the chemical DPC don't work in solid concrete walls although I wasn't surprised he said that. I can't have EO as the power might be off for a while so I need Chemical and tanking.Only real issue here is not getting a professional in to do the injection is that right? Everything else makes sense?