Damp house! How do I rectify?

[sjee6]

Hi, this is my first post, I am in desperate need of help! I bought this 1920's terrace in December last year, didn't have a survey done and noticed fairly quickly that the house is suffering from severe damp issues, especially around the fireplace. The timbers are infested with beetle and need to be replaced, the external wall had cavity wall insulation (the white fluffy stuff) which I have recently had extracted. I am in the process of knocking the vestibule down as I believe it will improve airflow around the room, and allow the moisture to run off through the air bricks, as my house is on a bit of a hill so it's slightly tilted (the most damaged bit of skirting was on the vestibule wall). I have no idea what to do bout the fireplace, as the base is saturated with damp and doesn't really seem to be drying out, even with the subfloor open and ventilated. Piles of sand and rubble were left leaning up against the brickwork around the base of the fireplace. It has a bitumen damp course around the room, which I've just noticed has some fungus growing on it. The bitumen doesn't go all the way around the fireplace, so I'm assuming it's not how it was originally when it was built. I'm knocking the gypsum plaster off the external wall and planning to replace it with lime.

The last picture is the infected area in my kitchen, the rest of it is lime plastered and seems ok, but the area you see has had a gypsum skim but seems like there's something else behind it, at least at the bottom.

Anyways any ideas would be appreciated, and if you want me to provide more pictures I would be more than happy to do so. I really have no experience at all with DIY so I am almost at the point of despair right now. I am just hoping these issues can be fixed. Thank you in advance for your time.

Steve

 

[Notch7]

Hi Steve, don’t panic it can all be fixed.

It would be helpful if there were some external images.


I suggest you start by checking these:

1) is there ventilation of the sub floor - if not add more air bricks

2) check ground outside is below DPC and not bridging it

3) check rainwater goods, leaking gutters, downpipes etc are a common source of damp. Check that downpipes discharge into surface water drains that carry the water away from the building - if these are blocked then water can soak into the ground by the house.


There are various options to stop damp internally getting through plaster but it’s best to try and resolve the source of the damp first

 

[sjee6]

Notch7 - Thanks for the response.

Ground level at the front is quite high but I can't tell if its above the DPC.

The exterior is concrete rendered (K rend)

Rear has been decked out and they have decked around the pipes so I can't see what's going on their.

Moisture is always present after it rains. Seems like its coming in through the airbricks so I don't think there's anything I can do to stop it but I was thinking as long as the ground is flat and unobstructed by rubble or walls it should just run off into next door.

 

[sjee6]

 

[tomm12]

First thing would be to remove all damp looking floor to ceiling wall plaster & chimney breast plaster back to bricks then, whatever else your doing, the walls will be drying out. Remove the hearth for the the moment and dig out the soil below it. Are you going to keep the hearth or do something else with the hearth and fireplace?
Ditch any flooring or joists that even looks infected with bugs or rot. Strip all skirtings.

Youve not posted outside pics that were asked for so cant say anything about the outside or ventilation.
Fungus doesn't grow on bitumen so a pic of the fungus might save you some problems?

I would get shut of the deck it might be only causing you problems, you might have a blocked gulley below the decking, or at least remove the last two or three decking pieces for a look. Also remove the battens fixed to the wall.
Is the render bridging your DPC.

 

[Notch7]

Are the external wall solid or cavity -judging by the window reveals it may be solid

I would ditch the decking -its causing rain bounce above DPC level so the bottom of the wall is getting soaked

How far down does the K rend go -if it goes to the ground its bridging the DPC -it should finish at the DPC with a bell cast bead

Internally I would clear all the debris in the floor void and make sure your vents are working properly

If the brickwork continues to be damp -because its working up from ground level and or coming through the wall due to porous brickwork, then you might wish to look at oldroyd membrane for really bad walls

External walls may suffer condensation and damp -and those you should probably look at insulating.


By the way gypsum based plasters are highly hygroscopic and will show damp through them if the wall is damp. Lie based traditional plasters are breathable, but they arent if the walls are then painted with modern vinyl emulsion -they need painting with limewash or similar.

Personally I would look to create a damp barrier and finish with modern plaster systems

Oldroyd Xv Black Cavity Drainage Membrane (2.08 m × 20 m)

Studded black polypropylene cavity drainage membrane.

safeguardstore.co.uk

 

[JohnD]

The wet kitchen is likely plumbing leaks

Why is the decking so wet? Gutter or drain?

You need to pull it up before you fall through a rotten patch.

Stand back and take much wider pics, from roof to ground, back and front.

Indicate where the damp patches are.

 

[Murdochcat]

Without a survey - were you mad?

 

[sjee6]

My plan right now is to expose the original fireplace and keep it as a decorative feature. I can't use it because the chimney stack has been taken down. I want to knock off all the gypsum and replace with lime, and have a limewash finish. I would also like to have bare floorboards but most of the floor has been replaced with odd bits of plywood and chipboard - I might take up the ones from the bedroom and transfer them to the living room, is that a good idea?

The walls do have a cavity which I've just had extracted, so the vents are clear, I'll post a picture of the front of the property tomorrow.

Do I really need to ditch the whole joist if it's infected with beetle? Can I not just saw off the infected areas and re-bind them with plywood? Typically how much does a single joist cost? I can't seem to get an answer from builders or damp proofers who I've had round and I've had quotes from between £4000 to £8000 for them to do it themselves which just seems ridiculous to me. Is it a difficult job?

I like the decking but I guess I might have to ditch it like you say so I can see the drains.

Thanks for all your advice and guidance so far, I do appreciate it. I'll post some more pictures tomorrow.

 

[sjee6]

Decking is wet because it was raining when i took the picture

 

[JohnD]

Decking is wet because it was raining when i took the picture

It is sodden and rotting.

In a corner of waste pipes, downpipes, and drains.

Uncover them so you can find the leaks.

 

[sjee6]

JohnD - that is just from piles of rotting floorboards I left their until I dumped it all recently.

 

[JohnD]

JohnD - that is just from piles of rotting floorboards I left their until I dumped it all recently.

The decking boards are green and sodden.

 

[Notch7]

The walls do have a cavity which I've just had extracted

Ah yes, you did mention removing CWI, my bad.

Do I really need to ditch the whole joist if it's infected with beetle? Can I not just saw off the infected areas and re-bind them with plywood? Typically how much does a single joist cost?

Just replace them

C16 treated 170 x 45 is around £20 for a 3.6m length (span tables indicate a max span for that size timber of around 3.9m)

As you’ve taken up the floor, I think it falks under building regs and you will need insulation that complies with part L

I want to knock off all the gypsum and replace with lime, and have a limewash finish

I would still think about insulation on external walls

If you are getting in a plasterer you might want to look at costings before going down lime plaster route.

limewash is proper expensive, I’ve just used some on a listed property built in 1770s

I used Graphenstone, £24 for a litre of paint

Ecosphere White - The highest quality natural lime interior paint

"Eco-friendly interior paint made with natural ingredients that will brighten up any room. Shop Ecosphere...

graphenstone-ecopaints.store

 

[sjee6]

I was actually planning to plaster it myself, I don't care about it being level, I can probably never sell it anyway, not only did I not get a survey done but I also massively overpaid, even in top condition It's not worth what I paid. I don't mind paying extra for the limewash, still probably cheaper then wallpaper and I like the way it looks. Does It have to be used on lime plaster though? I can't hack off all the gypsum, they've gone all around the window and door frames, I can't re-do that, will it look odd?

I am now able to see through to the outer cavity above this gas meter box and It looks to me like It's been re-bricked at some point, or am I wrong? If so, why have it rendered?

Just about see the arch now in this fireplace, it's quite tall, do I need to know anything before knocking it out?

Cheers!