Solving penetrating damp?

[steelseries]

Hoping someone can help - @pigletjohn hopefully?

Recently moved into an 1850s stone & brick cottage. Front sitting room floor is lower than the outside pavement which goes up at an angle outside. The whole wall has salts coming through and is clearly damp in the corner at the bottom.

Had the damp surveyor out who predictably has quoted thousands to put in chemical DPC and membranes etc.

I now realise that that's not what I need, but I'm not sure what I need or who to ask?! All the "damp specialists" I can find locally talk about chemical DPC for rising damp!

I can’t help but I follow sympathetic_restoration on Instagram who is renovating an old house, and talks about how to deal with damp problems without resorting to modern ways (which don’t work). There may be some pointers there for you.

I’m going to @pigletjohn.

Few know more about this.
Expect questions OP!

Ah thanks @CrystalMaisie . We plan to be in this house for a while so don't want to do anything which will simply mask it, or make it worse!

I know that if it’s been plastered with modern gypsum rather than lime plaster, or bodged with cement, that can cause damp problems as the wall can’t breath. Good luck with it.

You say "outside pavement"

Is this your own paving, or a council owned street?

Because it would be preferable to trench round the house and lay a French Drain or similar filled with pebbles or cobbles that do not enable capillarity.

Is it brick or stone at the bottom of the wall?? Coursed or rubble?

How old is it?

What is the internal floor really made of?

Have no truck with silicone injections.

Look for drains, gutters, downpipes, gullies and waterpipes that may be supplying water to the damp patch

Post some photos please.

Hi @PigletJohn

1. Council-owned street in a Conservation area.

1. It's rendered but I think stone. Not sure about the second part of your question I'm sorry - this is all new to me! Maybe you can tell from the picture?

1. 1850

1. Looks like it's been concreted

1. Can't see any drains or gullies which would be supplying water - tarmac pavement goes right up to wall...

Internal floor pic - it's solid

Thank you @CrystalMaisie & @PigletJohn

Is it just the small grey building? Possibly an infill newer than the neighbours, so construction may be different. Brickwork is easier to deal with than stone.

I can see a gutter. Where does it drain to?

And the neighbours downpipes?

If the blue line is the level of damp, I bet the source is close to the highest point (not just coming from the ground) and I'd start by looking for a leaking gutter or downpipe, as it is so high. If it is at the party wall, rain might be entering at the roof joint. There needs to be lead flashing (not black paint, sticky tape or a mortar fillet).

Find the Historic Buildings officer at your local council. She will be familiar with the problem and remedies.

Thank you. The small cream-rendered bit is the room in question. Looks from this side shot that the room is actually brick.

The line is not where the damp has rises to, it is my indication of where the level of the road outside is, sorry if that wasn't clear.

The house is detached. The gutter drains into the ground where orange arrow indicates.

Will look into the Historical Buildings Officer.

OP, in the 2nd set of pics where there looks to be one different coloured brick down at pavement level just to the left of the gate post.

Is it an air brick ?

Hi @tanstaafl - no I don't think so, I think it's decorative rather than functional. It's solid.

What’s behind the gate?
A path, steps somewhere.
I’m wondering if water is being directed to the corner of the outside where the gate post is.

@tanstaafl yep exactly - a couple of steps and a path to the garden. I think I'll have to take another look to see if the drain is leaking or something.

Do you mean the downpipe goes into a gulley or drain, or just onto the ground?

Does the gutter leak much, and is it blocked?

How far below pavement level is the internal floor?

@PigletJohn it goes into a drain. Gutter doesn't leak and isn't blocked (I've checked).

See pics on how far below ground level the room goes. The whole front wall of the house is damp (salts coming through paint) but the deepest corner is the worst.

The gulley is quite likely broken and leaking, but please post some pics.

Is it next to the wet patch?

The room does look surprisingly deep.

Have you had your drains CCTV'd OP?
I have a similar problem in my not quite as old as your house and said similar.
No leaks, gutters clear, everything draining - but, unbeknown to me, not draining as and where it should be.
Seeping quietly into the ground around the house.
Drain CCTV showed several cracks in the pipework and 1 area (thankfully rainwater not sewage) which needs digging out and replacing/repairing. Am waiting on dates for repairs as we speak.

It also looks, to my untrained eye, as if there has been some sort of waterproof screed type stuff laid on the floor of that room? - the black stuff in your internal floor photo.
If the floor is damp, the moisture can't get out so will go up the walls instead.

I feel your pain.
The joys of old property eh?

@PigletJohn some more pictures of that outside corner this morning. Hard to tell if the pipe is leaking as it just goes straight into the ground. I will get drain CCTV to see if there's damage.

I've just seen there is a chemical DPC that has already been injected at the base of the entire front and side of the cottage. And yet they're quoting me to do it again!!

The whole corner where the damp is inside looks damp outside.

If there are salts in the plaster they will draw water in from the air, even if the source of the damp has been fixed. This means the paint will go on flaking off etc.

Nut as the base of the wall is brick and below ground, I would have thought it would just be absorbing moisture from the ground under the pavement anyway. I can't see how youd get a french drain in under the pavement - So not sure there is any alternative to tanking up the wall to above grade. There are tanking systems that supposedly let vapour put but resist capillary action. This is what we had to do with to the base of a wall in porous stone. It seems to have done the trick, after years of musty smells, been fine since. Our wall is very thick though, so v slight difference there.,

Also before you do any more work/decoration, have you checked for radon? Fixing damp and fixing radon may need similar measures so its a good time to do it if it's needed.

The downpipe is modern black plastic, so a recent replacement. It looks like it goes into old concrete. The nearby brickwork is very eroded and spalled showing it has been wet for many years. The ground also looks wet.

My guess is that there is an old drain in the ground, there might once have been a gulley. It will be made of old salt-glazed clay (like a Brown Betty teapot) which IME are always cracked, broken and leaking, typically since 1940.

If you get your garden trowel and dig round it, I think you will find the ground and brickwork are very wet.

There seems to be a side alley between the buildings, and drains commonly run from the back of the house, along the side, to sewers under the road. Look for other drains and manhole covers. Depending on age, the soil pipes and the rainwater drains may be combined. In this case you may find red worms and wild tomato plants, both thrive on damp soil and decaying organic matter.

In some districts there is a back lane and services may run under that.

p.s.

It looks like you may have courses of dark blue bricks at about ground level. Are you near Staffordshire, or is there an old canal or railway nearby? They will be useful in resisting damp if you can cure the leaks and repair the brickwork. You may also need to reduce the ground level so there are at least two courses showing.

If they are just red bricks with black bituminous paint, that's no good.

Much damp is associated with water leaks and incorrect ground levels. One thing you can certainly say about silicone injections is that they do not repair these faults.

Incidentally, the gutter brackets at the front are interesting. I saw similar at an old family house in Gloucester of similar age, with similar damp. In that the iron gutters had actually rusted through. Can you take some pics for me please? I think they are unusual.

@PigletJohn we are indeed near Staffordshire - on the Staffordshire/Derbyshire border.

What's the relevance of the railways nearby? We have a few old railways nearby. They are the black bricks you mention (not painted).

I think we need to figure out where that modern plastic pipe is going then. And whether whatever it's going into is cracked.

Ps these are the brackets