Damp in Victorian house - conflicting advice..HELP!

[TO50]

I have your standard two up two down end of terrace house. Discovered I have rotten wooden floorboards in front room. Surveyor told me that path at side of house needed lowering by 150mm as it was breaching dpc but recommended a damp proof specialist to assess. So got a specialist in who has said to resolve issue i just need to replace rotten floor parts and they will use chemical on them and add another airbrick to front of house (there are two there already from different times before i moved in). I questioned treating the root cause being the side path and he said thats nothing to with them. Slightly confused that damp expert doesnt want to recommend resolving root cause.

Anyway, got two builders in to review. Builder 1 said just put french drain in on side of house and replace wood but dig down so room under joists or even concrete the whole floor. Builder 2 says remove path and lower and make path gravel and add air bricks into room, at least two.

I am now totally lost what is best way forward.

From photos you can see only one air brick to side and that there is no dpc as must be hidden under path. The back room has had a concrete floor laid too so this add some other confusion to my brain! Note path also has a crack on it a its damp there and that is where the worse rot is. There is next to no room under floor joists for air circulation and on looking under i can see rooten wood has been left down there before.

Really would welcome some guidance. I am on my own with no one to bounce this off so with the professional all saying different things I would welcome anyone else’s experience/ advice.

Thank you

 

[Todd]

Any wood touching soil will absorb the moisture, so yes dig down to clear this away, obviously replace the wood use treated c24 timber, I’d have a French drain along with lowering the path and adding vents for under the floor, check your other vents aren’t blocked too.

 

[Feltwell]

So, a few things going on there, but builder 2 sounds closest to the mark, and the "damp expert" furthest away! Don't concrete the whole floor, you risk a much bigger world of problems if you do that.

Sub floor needs clearing out so the joists are a few inches clear of the ground beneath, and all the rubbish removed. Damaged timber replaced, which might not be a whole joist, they can be jointed. No need to spray chemicals around.

The side path. I'm suspicious that the air brick is a small modern one, makes me think it was lower down originally!

A french drain is one way to go but their effectiveness is questionable, so it's better if you can lower the path level - 6" below DPC, and if you're ok with a gravel path then great as that will obviously let water drain through unlike the current concrete one.

Extra air bricks - possibly. The current ones need to all be clear, and the soil and rubbish being right under the joists will be stopping air from circulating properly. Ideally you have air bricks on opposing walls, but if not then front & side is the next best thing. If you've 2 on the front then for the amount of time it will take a builder to do I'd have 2 on the side as well.

Whilst the floor is up you may want to consider insulating between the joists.

If the rear room has been concreted, that *may* cause a problem, but you'll see when your floor is up. A concrete floor can - note *can*, not will - push moisture up into the surrounding walls if the damp proof membrane and damp proof course are not joined (which very, very rarely happens when a concrete floor is added later). This moisture can cause visible damp in the lower walls but can also cause any joist ends embedded into those walls on the other side to rot.

So - if that wall has any joist ends in it, you'll see when your floor is up if they are rotting. The other bad sign is if your back room has visible damp. If you can see no issues then I'd leave it as is - ideally it would be a suspended timber floor as it was originally, but if no problems are evident then it's a lot of work and cost to dig it all out.

 

[Cubist]

One time in a bar in London I overheard a conversation between two blokes who were arguing the toss about whether to treat the cause or the effect of any particular problem. One chap was adamant that it was far better to deal with the root cause(s) while the other took the view that the important thing was to manage the effects. After they had left the barman leaned over and told me that they were both 'damp specialists' and that the one arguing for treatment of the effects drove a Ferrari.

 

[Feltwell]

You do wonder what people think when the "damp specialists" hack plaster off to 1m high internally, then render with cement render with a waterproofing admixture. Problem is your average Joe doesn't think - they trust. Of course all the "specialist" is doing is locking damp in the wall and hiding it behind a waterproof layer.

It's happened here in the past, in my lounge, when it's pretty obvious the cause was deteriorated pointing on the brickwork outside plus a leaky porch roof. All now sorted under my tenure. The internal render I've left, as all seems bone dry now it's low on the list! At least I escaped the dreaded row of drill holes for an injected DPC.

 

[TO50]

So, a few things going on there, but builder 2 sounds closest to the mark, and the "damp expert" furthest away! Don't concrete the whole floor, you risk a much bigger world of problems if you do that.

Sub floor needs clearing out so the joists are a few inches clear of the ground beneath, and all the rubbish removed. Damaged timber replaced, which might not be a whole joist, they can be jointed. No need to spray chemicals around.

The side path. I'm suspicious that the air brick is a small modern one, makes me think it was lower down originally!

A french drain is one way to go but their effectiveness is questionable, so it's better if you can lower the path level - 6" below DPC, and if you're ok with a gravel path then great as that will obviously let water drain through unlike the current concrete one.

Extra air bricks - possibly. The current ones need to all be clear, and the soil and rubbish being right under the joists will be stopping air from circulating properly. Ideally you have air bricks on opposing walls, but if not then front & side is the next best thing. If you've 2 on the front then for the amount of time it will take a builder to do I'd have 2 on the side as well.

Whilst the floor is up you may want to consider insulating between the joists.

If the rear room has been concreted, that *may* cause a problem, but you'll see when your floor is up. A concrete floor can - note *can*, not will - push moisture up into the surrounding walls if the damp proof membrane and damp proof course are not joined (which very, very rarely happens when a concrete floor is added later). This moisture can cause visible damp in the lower walls but can also cause any joist ends embedded into those walls on the other side to rot.

So - if that wall has any joist ends in it, you'll see when your floor is up if they are rotting. The other bad sign is if your back room has visible damp. If you can see no issues then I'd leave it as is - ideally it would be a suspended timber floor as it was originally, but if no problems are evident then it's a lot of work and cost to dig it all out.

Thanks. I have now noted dampness to wall between front room and back room by the internal door. I have booked in “damp specialists work for mid January as earliest they could do just to get room useable. I will get more of floor up this weekend and have a closer look at wood joining back room. Wouldn’t surprise me if there is no dpc.

 

[TO50]

So, a few things going on there, but builder 2 sounds closest to the mark, and the "damp expert" furthest away! Don't concrete the whole floor, you risk a much bigger world of problems if you do that.

Sub floor needs clearing out so the joists are a few inches clear of the ground beneath, and all the rubbish removed. Damaged timber replaced, which might not be a whole joist, they can be jointed. No need to spray chemicals around.

The side path. I'm suspicious that the air brick is a small modern one, makes me think it was lower down originally!

A french drain is one way to go but their effectiveness is questionable, so it's better if you can lower the path level - 6" below DPC, and if you're ok with a gravel path then great as that will obviously let water drain through unlike the current concrete one.

Extra air bricks - possibly. The current ones need to all be clear, and the soil and rubbish being right under the joists will be stopping air from circulating properly. Ideally you have air bricks on opposing walls, but if not then front & side is the next best thing. If you've 2 on the front then for the amount of time it will take a builder to do I'd have 2 on the side as well.

Whilst the floor is up you may want to consider insulating between the joists.

If the rear room has been concreted, that *may* cause a problem, but you'll see when your floor is up. A concrete floor can - note *can*, not will - push moisture up into the surrounding walls if the damp proof membrane and damp proof course are not joined (which very, very rarely happens when a concrete floor is added later). This moisture can cause visible damp in the lower walls but can also cause any joist ends embedded into those walls on the other side to rot.

So - if that wall has any joist ends in it, you'll see when your floor is up if they are rotting. The other bad sign is if your back room has visible damp. If you can see no issues then I'd leave it as is - ideally it would be a suspended timber floor as it was originally, but if no problems are evident then it's a lot of work and cost to dig it all out.

Back room has dampness on lower wall by internal door (only noticed since replies) will get boards up fully in front room to have a look.

There is no way the air bricks have room for air to circulate given the height of floor.

 

[TO50]

Thank for your prompt responses. Hope this isnt too draft to ask but if builder digs down and removes earth below will it impact structure?

 

[Cubist]

Thank for your prompt responses. Hope this isnt too draft to ask but if builder digs down and removes earth below will it impact structure?

The objective would be to remove only sufficient material to expose the timbers and any brick piers supporting them. No excavation work to any other depth should be conducted anywhere within about a foot from a wall. If you are hiring a builder make sure to ask him/her some very specific questions about 'how' the work will be done.

 

[Feltwell]

Thank for your prompt responses. Hope this isnt too draft to ask but if builder digs down and removes earth below will it impact structure?

No, you're fine. If they're half decent they'll dig out just enough to sort the problem and no more! Builder would have to go down to the very base of the walls before there would be any concerns.

 

[Feltwell]

Thanks. I have now noted dampness to wall between front room and back room by the internal door. I have booked in “damp specialists work for mid January as earliest they could do just to get room useable. I will get more of floor up this weekend and have a closer look at wood joining back room. Wouldn’t surprise me if there is no dpc.

Is that wise considering how bad their advice has been? Builder 2 sounds more sensible.

 

[Todd]

Thank for your prompt responses. Hope this isnt too draft to ask but if builder digs down and removes earth below will it impact structure?

Don’t let them inject the walls with anything, read this and watch his video too, https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html

 

[TO50]

Don’t let them inject the walls with anything, read this and watch his video too, https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html

Thanks i have read every page of their webiste and thats why i really was unhappy about ‘damp specialist’ although they wont be injecting just replacing boards and joists Nd putting chemicals on them. Plus putting additional air vent which wont make any difference when there is no room for air flow under boards and dpc covered . I did argue the toss with him but he wasnt having any of it…i even mentioned Heritage House. Best resource ever!

 

[malcolm]

That doesn't sound like it is going to work. If you replace stuff like for like you'll end up with the same problem.

The way to fix it and stop further rot is to make sure the wood keeps dry. Knocking out and replacing the path at a lower level, clearing out the loose junk under the joists, and making sure you have functional air bricks would be the starting point.

Magic chemicals won't do anything if the wood is damp (and aren't necessary when the wood is dry).

Can you post photos of the rot? Should be possible to come up with a cheaper plan that actually works and preserves the fabric of the building.

 

[Lacan07]

You do wonder what people think when the "damp specialists" hack plaster off to 1m high internally, then render with cement render with a waterproofing admixture. Problem is your average Joe doesn't think - they trust. Of course all the "specialist" is doing is locking damp in the wall and hiding it behind a waterproof layer.

It's happened here in the past, in my lounge, when it's pretty obvious the cause was deteriorated pointing on the brickwork outside plus a leaky porch roof. All now sorted under my tenure. The internal render I've left, as all seems bone dry now it's low on the list! At least I escaped the dreaded row of drill holes for an injected DPC.

Of all the crap pulled by the damp specialists the dpc injection is probably the least worrisome. It might work a bit, it might not work at all, but it wont cause too much damage either. Waterproofing / tanking however is much more difficult to reverse I would have thought.

 

[paulc]

Of all the crap pulled by the damp specialists the dpc injection is probably the least worrisome. It might work a bit, it might not work at all, but it wont cause too much damage either. Waterproofing / tanking however is much more difficult to reverse I would have thought.

The row of holes drilled in to the bricks will advertise for ever more that inappropriate work has been done. At best, the cement filled holes look ugly.

 

[TO50]

That doesn't sound like it is going to work. If you replace stuff like for like you'll end up with the same problem.

The way to fix it and stop further rot is to make sure the wood keeps dry. Knocking out and replacing the path at a lower level, clearing out the loose junk under the joists, and making sure you have functional air bricks would be the starting point.

Magic chemicals won't do anything if the wood is damp (and aren't necessary when the wood is dry).

Can you post photos of the rot? Should be possible to come up with a cheaper plan that actually works and preserves the fabric of the building.

They are only planning to replace wood and pit chemicals on what they replace. I think i will get a proper RICS surveyor come in and spec the work so i have more chance of a builder doing what is needed not what they want to do. No matter what I say they all want to do different things and all i want is what everyone on here has confirmed…lower path below dpc, clear under floor, replace wood and add air bricks.

 

[TO50]

The row of holes drilled in to the bricks will advertise for ever more that inappropriate work has been done. At best, the cement filled holes look ugly.

Certainly no drilling of holes and that just advertises to the world you have damp and not solved it

 

[TO50]

That doesn't sound like it is going to work. If you replace stuff like for like you'll end up with the same problem.

The way to fix it and stop further rot is to make sure the wood keeps dry. Knocking out and replacing the path at a lower level, clearing out the loose junk under the joists, and making sure you have functional air bricks would be the starting point.

Magic chemicals won't do anything if the wood is damp (and aren't necessary when the wood is dry).

Can you post photos of the rot? Should be possible to come up with a cheaper plan that actually works and preserves the fabric of the building.

The photo of the boards is as good as it gets. If you put your hand under the wood just breaks away like dust. No weird fungus looking stuff from what i can see

 

[Matt Green]

Almost certainly wood-boring weevil damage. No need for any chemical treatment, address the source of water and repair the damage.