dAMP pROOF OLD RETAINING WALL

[r896neo]

I have applied two coats of permaseal tanking slurry on the inside wall which seems to have helped a bit (it is a breathable cement based product), but really want to sort out the problem properly.

 

[joe-90]

And doing what I say will sort it cheaply and properly. What's the point in digging up the garden and wasting thousands of pounds?

 

[theoldun]

If you want to do the job 100% right so that it will last another 150 years with no damp whatsoever and every tree hugger and conservationist wanting to come and have a look at it, then let me know.
However budget for £4000.00.
Take it the answer is no. Okay confirm the following for me please and will give you some answers and costings. Is it a standard outside external toilet. WC pan only Any heating. Any window. Is door from main house or from external. If external is it a wooden door with gap under bottom. Size of building about 900x2100 say 3ftx7ft in old money. Note you have applied liquid membranesa to walls, but are internal walls plastered or in stone face. Know all I need to know about outside.
Looking to see how much is worth spending.
oldun

 

[joe-90]

Any photos?

 

[gemmyw]

Hi, I haven't got any photos sorry. The old outside toilet is the dimensions you have said, however on the side of the house previous owners have built a conservatory approx 18' x 8', and old outside toilet comes off the side of it, so loads of ventilation, and there is also a radiator in the conservatory. Haven't got a door on the toilet yet, or even a toilet yet!

There is no way I can afford £4k or even 1/4 of that i'm afraid. To be honest if I have the money I would knock it all down and start again conservatory included!
Internal walls are concrete rendered. Trouble with battoning and drylining is I don't have that much room to do it, and the timber batons would go rotton if any damp came through wouldn't they?
Is it worth outting a dpm on the outside to the depth i've dug or will this not help?
I would be very grateful for any advice.
Thanks
Gemma
[/img][/url]

 

[Norcon]

I would dig it right down to below the inner floor level.
Then place a membrane against the wall. Drain pipe if possible at an appropiate level. (As low as possible) And backfill with a 2" aggregate for about .5m (above the drain pipe only with compacted clay below , if drainage level problems exist) and then refill the excavated material removing the excess from site.

A very tough membrane you can get has a dry like glue on one side.
If this becomes perforated with the backfilling process or water ingress past the sides and then subsequently wet, the glue is activated and becomes a very sticky porridge like sealing substance.
Forget the name of it but someone may know. We've used it a few times.
For belt and braces a roll of geotextile membrane over the glue backing membrane from top level down to base of aggregate level.
A 20m roll is about £400.

 

[joe-90]

Hi, I haven't got any photos sorry. The old outside toilet is the dimensions you have said, however on the side of the house previous owners have built a conservatory approx 18' x 8', and old outside toilet comes off the side of it, so loads of ventilation, and there is also a radiator in the conservatory. Haven't got a door on the toilet yet, or even a toilet yet!

There is no way I can afford £4k or even 1/4 of that i'm afraid. To be honest if I have the money I would knock it all down and start again conservatory included!
Internal walls are concrete rendered. Trouble with battoning and drylining is I don't have that much room to do it, and the timber batons would go rotton if any damp came through wouldn't they?
Is it worth outting a dpm on the outside to the depth i've dug or will this not help?
I would be very grateful for any advice.
Thanks
Gemma
[/img][/url]

Roofing battens are very flat and you'd lose little room with them. They are also pressure treated so last for decades.

You say the big fix is too expensive and the little fix means you lose an inch off the room so you won't do it. Sorry, but if you keep finding reasons not to do something then you'll just have to live with it. We can't help you if you refuse to listen.

 

[gemmyw]

I'm not refusing to listen at all! I'm very interested to hear what you all have to say. I'm not a builder.
I don't have the money to do the big fix, I have someone coming to have a look at it this afternoon, so at least now I am well informed, and will hopefully know what he is talking about!

 

[theoldun]

Hi,
To be honest it wasn't awful before, but the tanking slurry has worked, I have a few patches of damp coming through but probably only covers about 15-20% of the whole wall if that.

Initial remedial works should really be carried out externally first, but to achieve this it means excavating approx 4 cube metre spoil to achieve a working area 3metre long by 600 wide. Spoil will have to be deposited well clear of excavation and adequate shoring and jacks for support for soft banks. Not a job for a DIYer.
In my opinion any one on this forum who advises a DIYer to excavate a 2100 deep trench, without explaining the danger implications of working along side a soft face, clearly has no knowledge of the building industry or Health and Safety. Without correct shoring a slide slip could put down 3 tonne spoil every lin metre.
So the most practical and cheapest option is to tackle it from inside, however must stress this is not a long term fix, possibly last 10 years or so.
We would have used a Newton membrane internally but unless you go to a specialist company, you will have a job to find anyone who knows how to use and fix it correctly, so to keep costs down you can apply two coats of Feb Hyprufe liquid damp proof membrane on the external rendered walls. You can do this yourself, follow instructions on can. You have appox 5ms so 5 litres will just about do. Cost about £35.00. Reason we use this one now, is that IKOpro Synthaprufe is no longer available and Feb is the nearest we can find, in as much as that it is non breathable.
You will have to find a chippy next for a Saturday morning to stud and board. You will need approx 21m of 25x50 treated batten at 600 vertical centres with a horizontal noggin at 1200 down and at bottom. Cost about £13.00. Three sheets 12.5mm foil backed plasterboard, Duplek Vapourshield or similar. Cost about £27.00 Fixings, allow £8.00. Chippy for half a day? No idea what wages are like round your way. My way chippy for half day costs me £80 to £140.
You want plasterer now for half a day. Bag Multi finish about £5.00 and some scrim, about £3.00 but any decent plasterer should have enough in his van. Half days wages for spread £80 to £140.
Sweet talk your chippy to come back and run skirting round on completion.
Total say £250.00 to £450.00. If you get a quote under £500.00, then you are not getting ripped of.
One thing must stress. Whilst this wall has stood and retained for 120 odd years, and could possibly go another 100 years, mother nature is a funny old girl and is always trying to catch you out. What I am saying is that even though the old wall may possibly be 300mm thick, she is not a designed retaining wall and the old girl should always be treated as suspect.
It would have been nice to have had some external filtering and drainage, but the ground must be free draining other wise the old girl would not be still standing. She would have paid the toilet a visit a long time ago.
Hope you have gained some ideas.
oldun

 

[Norcon]

In my opinion any one on this forum who advises a DIYer to excavate a 2100 deep trench, without explaining the danger implications of working along side a soft face, clearly has no knowledge of the building industry or Health and Safety.

You're wrong but you're entitled to your opinion.
fyi I was explaining how I would go about rectifying the problem. We did one a few weeks ago on a 3m excavation x 22m long with a soft embankment.
No problems and no shoring props. Wonder why?
And it didn't cost £4k to our customer. Wonder why?
gemmy is under no obligation to do what I do and by the sound of it he's not going too anyway.

Granted I have walked away from jobs in my time wondering why myself and my men are still alive.
Roll on the h&s lecture.

 

[gemmyw]

Thanks for all your thoughts, the builder I had come out to look at it, agreed that tackling from the outaide is a no go, as I said before I can't even get a mini-digger to the area, (unless I crane one in and even then I'm about 100ft from the road. He suggested tackling it from the inside and has suggested similar batonning and dry-lining with a dmp between.
Still haven't got a price from him though!

Thanks again,

 

[joe-90]

It's not a big job and should be in the low hundreds.

 

[RedHerring2]

Feb Hyprufe liquid damp proof membrane on the external rendered walls. ............ . Reason we use this one now, is that IKOpro Synthaprufe is no longer available and Feb is the nearest we can find, in as much as that it is non breathable.

How come you say that 'oldun?
I've just bought some Ikopro Synthaprufe LAC from Selco today, and I found this:
http://shop.parkerbs.com/product/Ikopro_Synthaprufe_Original_5L_H00037