Posted: Mon Jan 12, 15 7:47 pm Post subject: Renovating
I wasn't sure how to title this but we are beginning renovating our house. It's a combination of a very old house with later added Victorian wings and "challenging" for far too many reasons. We are insulating from the outside which might be of interest to some of you. It's made from huge lumps of stone, probably straight from the beach which is about hundred yards away. (See above note about challenging...)
Scaffolding goes up on Wednesday apparently so we first of all had to start to solve one of the big problems. The driveway used to end at the window sill. The trench is about three and half feet deep and exposed several generations unsuccessfully trying to solve the damp in that side of the house. All suggestions would be appreciated. My concern is that we cannot slope it so it meets the drive in anyway as it's too steep.
kGarden
Joined: 01 Dec 2014 Posts: 178 Location: Suffolk, UK
Posted: Mon Jan 12, 15 7:55 pm Post subject:
I wasn't happy with a slabbed terrace here which looked like it had been laid rather high, with respect to damp course.
We dug a trench all around the house and laid a French drain in it (perforated corrugated [flexible] pipe bedded on a bit of gravel and covered with same). Slabs are relaid with a narrow gap next to the house wall (and inch or two) which lets the water (running down the walls, or coming towards the house from the slabs) into the gravel trench, and from there to the pipe. The perforated pipe is Y-joined into the rainwater downpipe's pipes.
The problem with a french drain here is that it's deep so if something blocked it we would be stuffed.
On the inside the window sill is 80cm off the floor. (The others in the room are at different heights. ) We are thinking a wider gap left open.
(What I actually wanted was a gently sloping driveway and a lovely green lawn that came graciously and gracefully up to the windows. I am slowly letting go of this dream.)
if you have 800mm from sill to floor inside(stone floor?)about 1000mm to the base of the drain/gully outside would be a good bet .
inside remove all plaster,needle gun to give a good key and render in 2 coats of waterproofed 4 to 1 sharp sand/portland,finish with a multifinish skim
i would usually say re plaster to about 1,25 m high but as YOU ARE SO NEAR THE SEA there is a high chance that there is a lot of salt in the walls and plaster,get rid of it all the way to the top ,this will reduce the hydroscopic absorbsion,wicking etc etc and after a year or so drying out should give a decent dry surface to decorate .
if it is a stone floor it might be worth lifting the slabs and digging out enough to blind it with sand fit a 1000gm polythene damp proof membrane and relay slabs or a concrete floor
if it is carpet over stone or concrete a dodgy but cheap alternative to relaying the floor is to put the dpm under the carpet and underlay
that often helps but can lead to mould and or water being forced into the walls .
do it well isnt cheap but it will work better long term,do it cheap might help a bit but wont work long term
if it is stone injecting the masonry or mortar might or might not help for the extra couple of hundred quid i would do it
originally the inside and out would probably have been lime washed which breathes and allows salts to crystallize for brushing away and combined with drafts and open fires would have been fairly cosy . stripping the external paint and using lime wash instead might help quite a bit.
originally the inside and out would probably have been lime washed which breathes and allows salts to crystallize for brushing away and combined with drafts and open fires would have been fairly cosy . stripping the external paint and using lime wash instead might help quite a bit.
She is going to fix insulation on the outside walls & then ? clad or render I suppose
A wider gap left open to below floor level is the best solution for your damp.
Yep.
Outside ground being higher than internal floor is never a good idea.
Suggest dig outside to below internal level and build brick/rendered block wall where you've cut tarmac. Finish wall say 6 inches above tarmac to act as a kerb. Or maybe a low wall with piers and railings.
1. Tank externally with a waterproof render up to soil level (having removed existing render to that level)
2. Insulate externally, ensuring that anything underground is guaranteed waterproof (extruded polystyrene?), backfill.
3. Speak to a local damp proofing firm about the best way to deal with the damp coming up through the walls
4. Possibly use a waterproof plaster part way up internal walls (depending on what the damp proofer says)
5. Use waterproof insulation under the floor
You could clad or render the outside afterwards
**EDIT** Just reread dpack's post, all sounds sensible but I'd also insulate under the floor
So - the damp doesn't come up from the ground except in the sense that it flowed down the slope and into the walls. The floor in there is dry and beautiful, it's wooden blocks laid over very efficient under floor channels. I don't think we will have to do anything to it. Fingers crossed. On the other hand the wall next to that window is falling off. The outer walls will be clad and then nothing will be done to the inside surfaces for at least a year possibly two on that side of the house while it all dries out (and probably falls off )
The windows in there are wrecked. Although 200 years of being damp still compare favourably to the less than twenty year old plastic ones in two rooms upstairs
Funnily enough our neighbour and friend is a damp proofer and will likely be doing the internal cladding one day. I will ask him about this specifically. We have discussed tanking. I think there may be a slight tension between Jack and I living here and our great grandchildren living here. (It's a farmhouse, same family, forever, theoretically)
dpack, I will remember that plastering when we get to that stage, thank you. Jack did roll his eyes when I said I would be asking on here and said that someone is going to mention limewash... In an ideal world, yes, but this is bloody big lump of house and we can't afford it.
We are going to have to leave a gap aren't we. Oh well at least we can see anything happening then.
Did quite a few damp proof injections in the 80's - worked pretty well on brick but we only did one on stone and that was a specialist job with electrolitic terminals. I'm not sure now How it worked - but worth finding out because it worked !
We also took up the floors and laid hot asphalt floors turned up the walls.
Saw the guy about 8 years later and he was still pleased with the dryness situation
i didnt like to mention hot asphalt but it can be useful in the right places
i understand the tension between best and affordable and recommend best you can afford even if that means one piece at a time .
my lime and drafts suggestion is firmly based in the 18th c and remedial work is a 21st c job.
the dig a ditch tactic will help lots and if it is filling up cos it cant drain naturally a sump pump is a small cost compared to a wet house
finding someone who knows this sort of stuff and is local enough to do a mk one eyeball and tell you truth about what you are dealing with and then suggest a selection of options is a good place to start
on the plus side solid floors are better than wet timbers
'Rising damp' is a myth peddled by the damp industry - penetrating damp is the usual problem. Injected DPCs do not work on rubble stone. Anyone who tries to sell you one will be relying on the tanking inside to keep the damp at bay - but after three years or so you'll see it reappear about three feet above floor level, where the tanking stops.
And if they offer a guarantee, smile and move on. I've never known any damp company honour a guarantee. Most go bust or reconstitute themselves every few years to avoid paying out.
French ditch, land drain, below ground tanking and breathable materials is the way to go.
French ditch, land drain, below ground tanking and breathable materials is the way to go.
that seems quite sensible with the caveat that breathable outside and dry inside does give the options of wallpapers ,normal paint regimes etc etc
breathable inside is probably best done in lime based render and lime wash which is ok if that is the finish you and your descendants like
my vote would be impervious inside and breathable /easy maintained outside
the wood block floor is probably layed in pitch or asphalt and if it is ok now dont mess with it
wellington womble
Joined: 08 Nov 2004 Posts: 15051 Location: East Midlands
Posted: Thu Jan 15, 15 12:34 am Post subject:
I have no words of wisdom about damp (except move, but I presume you'd rather live with jack and he's unextractable) but sympathy with renovations of all kinds. There's always a finished room here if you need a break...
) We are thinking a wider gap left open.
Thank you
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