Where would you start with this damp scullery?

[Londonterrace]

Edit: Update at the end of the thread

Hello all,

I'm new to the forum and also the proud new owner of a London end-of-terrace, built somewhere between 1873 and 1890. Sadly it has undergone every unsympathetic 'improvement' possible, as you can see from the picture next to the neighbour's house. It's in a conservation area.

I was hoping to get some advice on tackling damp. The surveyor told us we had a damp problem and we needed a DPC and tanking. It didn't take much googling to discover that was bad advice but unfortunately, having lived in the house for a couple of months, the damp problem does seem to be real. The problem is worst in the scullery/utility room. The kitchen is in a two-storey rear "extension" (but original to the house") with a lean-to roof. The utility room (also original) comes off that. It is single story and has a lean to roof. It has plenty of evidence of damp - the wallpaper is bubbly, and the dehumidifer fills up fast. But it isn't wet or obviously leaking anywhere.

Because the house has been so thoroughly fiddled with, it has lots of potential sources of the damp, and I don't know where to start and was hoping to get some advice on what to try and tackle first. Here's the grand list:
1. The back of the house is rendered in strips, as the picture shows. The horizontal rendering makes me wonder if there was a previous injected DPC.

2. Internally, I can see plenty of pink poking out of the gaps where the wallpaper has peeled off. I haven't stripped it so don't yet know if this is patching or if it has been completely replastered.

3. The surveyor told us there is a gap where the mortar flashing of the roof meets the rest of the house.
4. The kitchen greywater and the rainwater all go into the same drain, which is right next to the wall of the house. The kitchen pipe isn't placed very well so it is soaking the cement around the drain, although away from the wall. I suspect this drain is contributing to the damp problem because the corresponding area of interior wall is particularly bad, with the skirting board here is completely rotten. But I'm not sure if this implies the drain is leaking somewhere or if the problem is the volume of water going through or the position right against the wall?

5. There is only one air brick, high up in the wall.

Other information:
- The floor seems to be concrete, with a bit of laminate on top. I'm not sure if this would have been the original floor/whether a concrete floor here is problematic?
- Outdoors, the ground is paving slabs, built right up to the edge of the house. The indoors is still a few cm higher.

- The room has a radiator.
- We're not filling it with condensation in any obvious way.
- The walls are 11 inches thick.
- The entire front of the house is rendered, but the side is not.

So, what would you do first?!
Any hints on the drains or floor gratefully received.

 

[Feltwell]

Welcome!

That's not been sympathetically treated has it? The bars are a bit full on as well! But congratulations on your new abode, I'm sure you can make it better!

So, where to tackle first on damp - usual rule is look up. Is the guttering doing it's job properly? Rain overflowing anywhere? Any splashing back onto the walls where the downpipe goes into the drain?

You mentioned the flashing having failed- mortar flashing is nearly always a bad idea, it inevitably fails. I'd get that replaced with lead, chased & sealed into a joint in the brickwork.

The pipe you show - so quick &easy to fix that so it discharges into the drain that I'd do that straight away.

If an injected DPC has been done you can usually see a line of holes in the exterior brickwork. External slabs being only fractionally below the interior floor is a concern - they're probably bridging the original DPC, which was most likely made of slate. I'd take a slab up and have an exploratory dig. Cutting back all the slabs against the house and digging out a trench is a good idea if the DPC has been bridged or if the slabs are only just under it.

Lots of other things you could do but that would be my starting list.

 

[Flyfisher]

Welcome aboard!

I can't really add to Feltwell's post (all of which I agree with, particularly the drain pipe - get that easy fix done asap) but it seems as if you're already aware of many of the likely problems and how to go about dealing with them in the appropriate way. In that respect it looks like the house is fortunate to have you as the new owner.

But oh what a depressing first photo showing the contrast with the rather lovely house next door.
I despair about what goes through the minds of people who think those sort of 'improvements' are in any way appropriate - even without the rather severe grilles.

 

[CliffordPope]

The roof angle seems very shallow for slates. Water tightness will critically depend on having a sound membrane.

 

[MatthewC]

So, where to tackle first on damp - usual rule is look up

Actually in this case you want to look down, as Feltwell goes on to say:

External slabs being only fractionally below the interior floor is a concern - they're probably bridging the original DPC, which was most likely made of slate. I'd take a slab up and have an exploratory dig. Cutting back all the slabs against the house and digging out a trench is a good idea if the DPC has been bridged or if the slabs are only just under it.

The slabs (or concrete or anything solid) up to the utility wal are a VERY bad idea. You need to lift the slabs (or cut them) so you have a foot gap between them and the wall. You also need to remove all that growth on them, especially anything close to the wall (which I did on my house before I had even bought it, as it was empty.) I'm not sure what the comparative levels are but the general thought is that the outside ground level should be 8 inches BELOW the floor level inside. So, in the gap you should remove at least 6 inches of the soil or whatever you find there, so that the base of the wall can breath and hence dry out a bit. Yoou could even dig out some more and add a bit of gravel, but still keep the top level down as much as you can.

And don't forget to look up as well, as Feltwell says. Check and fix all gutters, hoppers, downpipes and drains, as well as the roof itself (flashing and tiles). I did this on my house and the result was that it dried out and is still dry, 8 years later.

Have a look at my blog (see Contact thingy on right) back in 2010/11.

 

[Abi Cott]

I had a similar original lean to structure on my first house. The survey told us there were serious rising damp issues on the wall dividing the kitchen from the main body of the house. When we took the plasterboard off the ceiling you could see the sky. Definitely a case of falling damp, and some correctly applied lead flashing solved the problem.

I'd start with the drains, gutters and roof flashing and see if it made a difference before starting on ground levels and concrete floors.

I think the rule of thumb is that it takes a month per inch of thickness for a wall to dry out, so patience may be required.

 

[Londonterrace]

Thanks everyone for the warm welcome and the advice, which has been extremely helpful. It seems pretty clear then that the first two jobs are tweaking the drain and sorting the flashing. I think the guttering is OK in this part of the house but will have a good look next time it rains.

Re the drain, is it OK that the kitchen sink discharges into here (plus the dishwasher, once we add one in)? The bathroom water goes with the soil pipe. What I've read has left me a little confused but it sounds like the kitchen water should go with the soil pipe too? But the fact that it does drain into here wouldn't cause damp (if it went in properly, of course)? Apologies if these are ignorant questions. The third pipe going into that drain is the boiler run-off.

The roof angle seems very shallow for slates. Water tightness will critically depend on having a sound membrane.

That's interesting. I'll see if I can measure the angle and see from the garden what other houses along the terrace have.

I despair about what goes through the minds of people who think those sort of 'improvements' are in any way appropriate - even without the rather severe grilles.

I know, we have been saying this to one another about once a day and I suspect will say it plenty more in future! Yes, I hope we will be better owners and do something to improve the front of the house. I would like to restore the bay one day if we can get the money together.

 

[Feltwell]

Re the drain, is it OK that the kitchen sink discharges into here (plus the dishwasher, once we add one in)? The bathroom water goes with the soil pipe. What I've read has left me a little confused but it sounds like the kitchen water should go with the soil pipe too? But the fact that it does drain into here wouldn't cause damp (if it went in properly, of course)? Apologies if these are ignorant questions. The third pipe going into that drain is the boiler run-off.

No such thing as an ignorant question!

The answer is....it depends!

If your house discharges into a combined sewer - which given it's age it *probably* does - then everything leaves your property down the same pipe - rainwater, all water from sinks and toilets. So it doesn't matter that the kitchen water doesn't go directly into the soil pipe.

Some houses though have 2 pipes leaving, one for strictly rainwater only, one for grey water & sewage. Then you have to make sure that wrong connections are not made, e.g. sinks discharging down the rainwater pipe.

It gets more complicated again if you've had a an extension built as the rainwater from that may just be connected to a soakaway in the garden.

Find a manhole cover on your land, open it up, get someone to flush the loo and then afterwards turn on the kitchen tap etc and you'll soon see what is connected. I'd be surprised if it isn't a combined system.

None of which has anything to do with damp! Providing of course that under the ground the pipework is in good condition.

Hope that helps!

 

[Abi Cott]

I don't think there are any major issues with separate pipes going into the hopper other than the obvious one that it's a bugger to fit them all in.

When you have your kitchen fitted I'd expect the washing machine, sink and dishwasher to all feed into one 2.5" pipe. At the end of the day you're not likely to be using all of them simultaneously.


*not a plumber but I design kitchens for a living *

 

[Londonterrace]

Thanks both! I'll update the thread with any progress.

Abi, you've reminded me I have NO IDEA where the washing machine pipe goes. *Pushes thought to back of mind.*

 

[fernicarry]

None of which has anything to do with damp! Providing of course that under the ground the pipework is in good condition.

If you're going to be digging to lower the ground level as others have suggested then definitely go deep enough to expose the underground drainage to see what state its in.

Ours was all original clay and pretty much disintegrated. Lets just say that when someone flushed upstairs you knew about it downstairs shortly afterwards...

We also had about 8 different feeds coming in from all over the place in a huge tangle of pipes of various ages. Its now all nicely organised with everything feeding into an inspection gully.

At the same time we separated out surface and foul drainage. It still goes into a single outfall further downstream but at least that bit is up to modern standards.

 

[Londonterrace]

I'm back with an update and another novice question. The drainpipe is fixed and we now have some pretty lead flashing instead of the mortar, and have replaced some cracked slates. The mortar was indeed in places opening all the way into the room below.

My question is - how do I know if I've fixed my problem? I've got a humidity meter and haven't noticed any dramatic improvement in humidity readings yet. I'm still getting a big jump in humidity every time it rains but presumably that's to be expected to some extent?? There is an airbrick connecting us to the outside air after all. I had a go measuring the damp in the walls with a damp meter but gave up because it just seems to be a random number generator.

I know walls and plaster can take a long time to dry out. I'm tempted to just patch up the plaster, paint the room, replace the skirting board and wait and see if new damp makes itself apparent! Sensible strategy or not?

 

[MatthewC]

I know walls and plaster can take a long time to dry out. I'm tempted to just patch up the plaster, paint the room, replace the skirting board and wait and see if new damp makes itself apparent! Sensible strategy or not?

Sensible? Yes!

You say that you have found and fixed cracked mortar, so there's a good chance that it was the major (or only?) problem. Leave it until next summer and see what things look like then. When we did the entire roof on my house and so sorted the missing slates, bad pointing around chimneys, porous/split old lead in a box gutter and broken cement ridges on all the hips, it still took a couple of months to notice any change whatsoever. It was still drying out a year later!

BTW, re drains and sewers (earlier posts), having been made to look at my system recently (see another thread), everything used to go into the one main drain, but after doing the work on the house the rainwater (only) now goes into soakaways but all the grey water joins the foul in the main drain. As I recall, this was what Building Control said, as you don't even want the odd bits from your sink going into a soakaway.

 

[Owain]

Abi, you've reminded me I have NO IDEA where the washing machine pipe goes. *Pushes thought to back of mind.*

I wouldn't.

My neighbour's bath just discharged below the floorboards.

That's what happened when you bought a new build bungalow in 1968 ...

 

[Londonterrace]

I know walls and plaster can take a long time to dry out. I'm tempted to just patch up the plaster, paint the room, replace the skirting board and wait and see if new damp makes itself apparent! Sensible strategy or not?

Sensible? Yes!

You say that you have found and fixed cracked mortar, so there's a good chance that it was the major (or only?) problem. Leave it until next summer and see what things look like then. When we did the entire roof on my house and so sorted the missing slates, bad pointing around chimneys, porous/split old lead in a box gutter and broken cement ridges on all the hips, it still took a couple of months to notice any change whatsoever. It was still drying out a year later!

BTW, re drains and sewers (earlier posts), having been made to look at my system recently (see another thread), everything used to go into the one main drain, but after doing the work on the house the rainwater (only) now goes into soakaways but all the grey water joins the foul in the main drain. As I recall, this was what Building Control said, as you don't even want the odd bits from your sink going into a soakaway.

Thanks Matthew! I lost my nerve a bit a couple of days ago when I picked up a cardboard box of washing powder and the bottom fell out because it was so soggy but I think I'm going to go in there with a tin of white paint and see how much has fallen off by the summer. I can't believe how much drier the main house seems to have become, just from us living it and heating it.

 

[Londonterrace]

Abi, you've reminded me I have NO IDEA where the washing machine pipe goes. *Pushes thought to back of mind.*

I wouldn't.

My neighbour's bath just discharged below the floorboards.

That's what happened when you bought a new build bungalow in 1968 ...

:shock: :shock: :shock: *Pushes thought away even harder*

 

[plasticpigeon]

Glad you got that flashing fixed! My house is from around 1900 and also has rain, grey and foul water going into the same sewer pipe ie a combined sewer which is normal for old houses. I have grey and rain water into the gulley and foul into the soil pipe with nothing else attached but it could all go into the soil pipe, it's not important. If you think the drain below ground might be broken, you can employ someone with a camera to look at the drains or since in these houses the drains are usually very shallow by the house, I mean less than a foot, you could dig around the gulley and have a look. I also think it might be useful to have a more porous covering to the ground at the back of the house such as pavers or bricks or even gravel where rain water can drain through it into the ground, rather than concrete which is pretty impervious. As others have said, the outside ground level needs to be at least 6 inches or 2 bricks below the inside level, and make sure that water run off when it rains, runs away from the house. Houses can take a long time to dry out. Concrete floors in old houses are not wonderful as it is very hard to lap the plastic membrane under the floor into the walls properly at the damp proof course. If the plastering behind the skirtings goes all the way to the floor, water can rise up the plaster as the interface between plastic membrane, wall and floor slab will not be very neat and water can get up this gap. If this iis the case perhaps chop out a few inches of plaster behind the skirting so that it is not touching the floor and bridging the damp proof course, and then put the skirtings back, or put bigger skirtings on. Sorry if I have repeated anything, it is a long thread and I only skimmed through it.

 

[Londonterrace]

Glad you got that flashing fixed! My house is from around 1900 and also has rain, grey and foul water going into the same sewer pipe ie a combined sewer which is normal for old houses. I have grey and rain water into the gulley and foul into the soil pipe with nothing else attached but it could all go into the soil pipe, it's not important. If you think the drain below ground might be broken, you can employ someone with a camera to look at the drains or since in these houses the drains are usually very shallow by the house, I mean less than a foot, you could dig around the gulley and have a look. I also think it might be useful to have a more porous covering to the ground at the back of the house such as pavers or bricks or even gravel where rain water can drain through it into the ground, rather than concrete which is pretty impervious. As others have said, the outside ground level needs to be at least 6 inches or 2 bricks below the inside level, and make sure that water run off when it rains, runs away from the house. Houses can take a long time to dry out. Concrete floors in old houses are not wonderful as it is very hard to lap the plastic membrane under the floor into the walls properly at the damp proof course. If the plastering behind the skirtings goes all the way to the floor, water can rise up the plaster as the interface between plastic membrane, wall and floor slab will not be very neat and water can get up this gap. If this iis the case perhaps chop out a few inches of plaster behind the skirting so that it is not touching the floor and bridging the damp proof course, and then put the skirtings back, or put bigger skirtings on. Sorry if I have repeated anything, it is a long thread and I only skimmed through it.

Thanks for all the info, plasticpigeon. I am going to put the drain survey on the to-do list, I think. I like the idea about cutting off the plaster to make a break with the concrete floor. What would this floor have been originally? Stone/terracotta tiles laid onto earth or something? I don't think there was ever a subfloor; there is a step down between the living area and the kitchen, and another between the kitchen and the scullery which is what brings the floor here so close to the ground. (Although the concrete patio I showed could well have involved some raising of the ground level, the level is actually lower than the rest of the garden; there is a step up to the lawn.)

 

[Londonterrace]

Came back to give an update: It's been several months since we did that roof repair. The humidity meter shows normal readings all the time, even during heavy rain. No new damage to the walls that I've spotted.

It's a bit early to say we definitely don't have a damp problem and I shouldn't tempt fate by gloating but the damp company wanted £5k for silicon injections and the roof repair cost £500.

Lowering the ground level is still on the (long) to-do list.

 

[Feltwell]

Excellent, always nice when people post back after a few months with good news!