Where to begin explaining :-( Cold, mouldy, depressing house.

[Chill-Pill]

Howdy All,
As per the title, where do I begin to ask for advice..
We bought a little detached cottage last year which was surveyed and pronounced damp free.
Only, it's turning out to be far from 'damp free'.
We have a single room bedroom extension stuck on one side of the house which is completely unusable in the winter as it's so very cold.
We had soaking wet skirting boards in the kitchen/dining room extension at the back of the house, with a little pool of water in the corner.
After much head scratching we realised that the concrete path had been laid higher than the interior floors and breaching the damp proof course. We have just ground out a channel around the entire house to get the concrete away from the wall, which is at least starting to dry up the skirting boards.
However, it seems the bedroom extension has suffered structural damage from a badly fitted down pipe and being buried under the path for years and the entire corner breeze block has disintegrated. Is it good enough to grind out the remainder of the original breeze block and replace?
Also, any ideas on the most economical way to insulate this bedroom so it can be used year round rather than just the summer? It's only a small room so struggling for room on the inside, but have very deep eaves on the outside so maybe external insulation's a better route?
Any help gratefully received.

 

[Doggit]

Firstly, it's a cold place, so I suspect you keep the doors and windows closed. If so, then you've got trapped moisture in the house condensing on the walls, and this is why the waters pooling. If you had damp, then the walls would be stained. In cutting a channel outside the property, you've possibly just taken away the cold earth, but that's not to say that it wasn't good thing to do.

What's the property constructed off? As long as you have good ventilation, and you don't need the walls to breathe, then external insulation is always a good way to go, and putting the insulation boards on the wall is a competent diy job, as long as you can get someone to put on the render afterwards.

 

[^woody^]

You begin by determining if you have a problem with penetrating damp or condensation damp. If you can't do that yourself from threads on here or elsewhere, then you need a survey from a suitably experienced person, and not a salesman from a damp treatment company.

You also need to work out if the existing heating system is adequate. So likewise for the above, but use a energy advisor or heating engineer.

 

[London Mike 49]

I would start by hiring a dehumidifier or two and take as much of the moisture out of the property as possible. I am not a builder but I would think it sensible to replace the breeze blocks , then fix kingspan external wall insulation panels to the out side and batten out and fix a breathable /waterproof membrane over the whole arena ( the sort that pitched roofs are lined with ).
It won't look pretty and you will have to do the job properly next year in the summer, but it will get you out of trouble for now.

Mike

 

[Hugh Jaleak]

Have you asked the surveyor how it could be declared 'damp free' last year, yet now you have problems of this magnitude! ?

 

[endecotp]

What is the construction of the walls?

 

[Chill-Pill]

Hi all, firstly sorry for the very late reply and thanks to everyone who responded to my post - very much appreciated.
The extension it seems is made from cinder block with the two holes in. With the width of the wall, I would say double skinned, but almost sure no insulation material between them.
The damp is almost certainly not condensation as the walls do not feel wet, are not mouldy etc. There is a very distinct fusty smell behind the skirting boards and the walls are very cold, but not wet. As mentioned earlier there is a drainpipe that is voiding down the back of a drain which is against the far wall of the room. We have dug this out and several of the cinder blocks have disintegrated here, totally gone. So it looks like the constant water flow has saturated the wall and possibly sub-floor. Funnily enough there is not a great deal of damage internally, just fusty smells and very cold. Maybe the air holes in the blocks have afforded some protection - don't really know.
We have yet to find the damp proof membrane in the walls, so either, there isn't one, it's at least 8" below ground level or it's hiding somewhere high up behind the render - none of which are great scenarios.
We are in agreement that Kingspanning the walls would be a good idea, however because the walls are so wet, we feel we should wait, use a dehumidifier and Kingspan once the walls have dried out.
Don't actually think that we will ever get this room to a reasonable standard of warmth and dryness, but would at least want to stop it deteriorating any further.
The surveyor issue, well that's completely our fault. We made the monumental error of accepting a report that had been done for a previous potential buyer of the house which stated there was no damp, no issues whatsoever, but we have found MANY. Our stupidity and being too trusting for our own goods. We found out after the house was purchased that a survey done for someone else, even if you pay for it, is worthless. There is no comeback whatsoever on the surveyor or their insurance. A lesson painfully learned.

 

[^woody^]

You dont have to see condensation dampness on the surface of walls like you do on windows.

Get your own surveyor's report

 

[motorbiking]

You may still have a claim for the survey... Not against the surveyor, but against the person who presented it to you. Are you able to determine why the survey was so wrong? If you've been deliberately misled, you would possibly have a claim.

On the insulation front, generally - if you have a cavity - fill it, its the cheapest option and there are many grants and subsidies. If your internal walls are wet, its likely that your plaster is also poo too, so you can rip back to brick and fit insulation backed plasterboard (e.g. Celotex PL4025 or PL4040), both will double or triple the insulation performance of the room. PL4025 will probably not reduce the size internally as you'd fix it directly to the brick.

 

[^woody^]

No one can rely on a report done for someone else, and there is no liability if they do

 

[Chill-Pill]

You are right Woody. We only have ourselves to blame. The only thing we can do is try and sort the mess out ourselves.
Another route we could take is to Kingspan the inside with battons and infill isulation. This will reduce the room size I know, but will hopefully warm it up enough to be usable. Might also be the most cost effective option.
We were originally going to fill the cavity with insulation, but after further investigation we've decided that as we've no idea how well the walls were built - and going by what we've seen so far - it will be pretty poor - so cavity wall insulation could cause more problems than it fixes.
Doing external insulation too might also cause more headaches as, although we are competent DIYers, we have no experience of this particular job.
The only worry with internally insulating is if we create any bridging issues where the insulation meets the internal wall. So much to think about and not a great deal of experience unfortunately.

 

[Chill-Pill]

You may still have a claim for the survey... Not against the surveyor, but against the person who presented it to you. Are you able to determine why the survey was so wrong? If you've been deliberately misled, you would possibly have a claim.

On the insulation front, generally - if you have a cavity - fill it, its the cheapest option and there are many grants and subsidies. If your internal walls are wet, its likely that your plaster is also poo too, so you can rip back to brick and fit insulation backed plasterboard (e.g. Celotex PL4025 or PL4040), both will double or triple the insulation performance of the room. PL4025 will probably not reduce the size internally as you'd fix it directly to the brick.

Sorry Motorbiking,
Meant to reply to your post with regard to the insulated plasterboard. There is very little visible damage to the internal walls (fortunately), so we are reluctant to hack this off. Could we still use the Celotex straight onto the plastered/painted walls? Does this have a greater thermal value than say, Kingspan? Would this product insulate enough to make a good difference to the temperature in the room? Could we tape the joints and use the Wallrock insulating paper system straight over it rather than plastering? Sorry for the many questions!

 

[motorbiking]

Have a look at insulation backed plasterboard, it can be mechanically fixed to the wall using hammer or frame fixers, there is no need for battens which will both reduce the room size and increase the U-value of the result. The PL4000 series I quoted is double foil backed, so should have good damp resistance too. There are many options for cavity wall filling, resin bonded blown bead, might even fix the water ingress problem as well as giving you a 0.5 or better U value. With 25mm internal insulation you may even bring the room to current levels.

EDIT:

Yes it can go on plaster
Yes it is better than kingspan allegedly
Yes you can tape and joint
No it wont impact its thermal efficiency.
The U value you achieve will depend on everything else, but even at 25mm I'd expect you to get to well under U = 0.35

 

[Chill-Pill]

Have a look at insulation backed plasterboard, it can be mechanically fixed to the wall using hammer or frame fixers, there is no need for battens which will both reduce the room size and increase the U-value of the result. The PL4000 series I quoted is double foil backed, so should have good damp resistance too. There are many options for cavity wall filling, resin bonded blown bead, might even fix the water ingress problem as well as giving you a 0.5 or better U value. With 25mm internal insulation you may even bring the room to current levels.

EDIT:

Yes it can go on plaster
Yes it is better than kingspan allegedly
Yes you can tape and joint
No it wont impact its thermal efficiency.
The U value you achieve will depend on everything else, but even at 25mm I'd expect you to get to well under U = 0.35

Thanks Motorbiking,
That's given me lots to consider and some hope we can fix this.
Appreciate your input and time.

 

[motorbiking]

Personally I'd hack the plaster off, since you are going to refinish the wall anyway and in my experience it will have blown, even if it looks ok and it will take half a day tops with a sds chisel blade on a hammer drill. It means you could improve the outcome another 20% without shrinking the room.

PL4015 R=0.7
PL4025 R=1.20
PL4040 R=1.85

U value is 1 / sum of R, so if you have.

brick (0.8) air (1) brick (.8) PL4025, the U = 0.263158, which would meet current building regs (england not wales)

EDIT, just checked the latest Kooltherm K118 which is in between PL4025 and PL4040 and it looks on par @ R=1.5