Rain coming in through a wall/floor, what do we need to do?

[Thurlow]

Idiot first time house owner question!

Today, after hours of torrential rain, we noticed that there was a little (2" x 1" at most) puddle of water on the floor right next to the skirting board, and further along the wall a similar sized patch of wet-ish wall just above the skirting board.

This is an 100 year old terraced house, the wall is the front wall under the bay window. I suspect that it's just the rain leaking in somehow, as that section of wall is nowhere near any pipes, and there's no damp problem in the house. This is a complete guess though!

What do we need to do? A quick Google suggests there are paints you can buy to damp proof the outside of the house, is that likely to do it? And if it doesn't work - proper novice question this - but what kind of tradesman do we call to have a look at brick work and damp?

Any advice from someone who managed to learn how to be a sensible and practical homeowner much appreciated!

PigletJohn is good on these things. Water finds the lowest point so it could be coming in from higher up than you think.

If the bay has a roof or any flashing on it check everything is in place and hasn't moved so rain can get behind it under it.

Check the pointing of the bay's brickwork - it may need attention.

Guttering - is it doing its job or does it need clearing or fixing?

if it's under the bay window, the gutter, windowframe or sill is probably leaking. Observe the ceiling though as bay roofs also often leak, especially if they are flat.

Look at the ground outside. It should be lower than the floor, and two brick courses (9 inches) below the dampcourse. There should be airbricks front and rear to ventilate the subfloor void, and they must not be obstructed by paving or flowerbeds.

Paint is no cure for damp. Do not invite someone who sells chemical injection or plaster into your home.

A gnarled small local builder, if recommended by a friend or neighbour, will have seen hundreds of houses like yours, built the same way and probably by the same builders, and with all the same problems.

Ah, we're new to the area so we don't know that many people to get a recommendation from!

No sign of anything on the ceiling, though we have found another damp patch on another external wall in the room. Will try and have a look outside at the weekend - there is a massive shrub against that wall, which maybe isn't helping.

There's no gutter above this bay window, the only gutter is up on the roof - will that make a difference?

I suppose our main problem is that I know we should look at things, but we don't really know what we're looking for!

Thanks

if you have a bay window, it must have a roof. Or do you mean there is a first floor bay above it, with the roof? There is probably a downpipe too.

Look at the gutter when it's raining, preferably with binoculars.

Look at the windowframe, the sill, the brickwork and any rendering, for gaps.

Get a parish magazine and look at the small-ads.

Check if your LA has a trusted & vetted trader scheme.

If the top of your bay is original, rather than felt, you may find that it has a small drainage pipe, going through it, rather than guttering. These can leak badly, as they get locked with silt and corrode.

We had an annual waterfall around the downstairs bathroom doorframe several years running. As it only happened in typical torrential december rain, it took a while to get to the source of it. Turned out to be a windowframe.

Also double check that you don't have any leaky downpipes as these can really soak a wall.

get a lader out and check all the guttering, idealy go out in the rain and look at the wall from the ground to see if the waters running down the outside walls and check the down pipe to see if water is using it or finding a different route to the ground.

the bush, cut behind closest to the wal it to allow air to circulate and avoid a algae patch growing on the wall. it will still look like it has the correc shape from front on

Thanks everyone. Even though the rain stopped last night there was still a little water pooling in a different place on the floor this morning.

I'm trying to work out the best plan of attack as OH thinks it is something we can fix ourselves (I have no idea why he thinks this!)

So if we check the guttering around the window, cut the bush back, and check the brickwork to see if anything looked damaged, that should give us a clue?

I suppose I'm confused because if it happens again, I don't know which sort of professional to call for advice - if we can't immediately see what's causing the leak, do we call a damp expert in case it is rising damp, a brickie in case the brick work is damaged, or a guttering person in case that has a problem?

It isn't rising damp.

Most "damp experts" are in fact salemen who sell chemical injection and replastering, neither of which remove the cause of the damp.

Oh - what's the difference with rising damp? If it's only been noticed after torrential rain does that mean it is going to be guttering or masonry problems?

It's going to be rain getting in somewhere, somehow. Rising damp seeps up from the ground. The problem you describe is rain getting in from above or the side if the wind is blowing it against the building somehow.

rising damp, if such a thing exists, describes moisture rising by capillary action through a permeable material. Capillary action in bricks is very limited in height, and the damp brickwork stops at the point where evaporation (due to ventilation of exposed surfaces) exceeds the rate at which capillarity can deliver water. Hence the treatment for damp at the bottom of walls revolves around lowering the height of wet ground, and improving ventilation e.g. by clearing out or adding airbricks, and by correcting leaking downpipes and spilling gutters which allow water to splash onto the foot of the wall, and removing absorbent coatings such as render or plaster which are better conductors of water than brickwork, or paint which prevents evaporation from the surface.

It does not result in pools of water after rain, which is indicative of a rainwater leak, which is what you have.

(there is a great deal of squabbling between people who sell chemical injections, and people who don't. One school maintains that rising damp exists and is a significant cause of dampness in buildings, and should be treated by pouring money into the pockets of people who sell chemical injections).

Here is a photo from Konrad Fischer, who built a small brick pier in a water tank. After some months, the water did not rise above the first course of bricks and its mortar joint. This has been built to a proper standard and in clean materials free of hydroscopic salts, and has free ventilation.

You will observe similar effects if you look at brick-built bridges, wharves and canal warehouses which are in contact with water. However where construction is poor, or there is damp earth behind the brickwork, or an absence of ventilation, the wall will be wet.

I remember reading an article in an home improvement magazine years ago about someone who had bought a listed cottage. It had no DPC whatsoever and no damp problem. The mortgage company was insistent on one being installed, though. Of course, as soon as they put one in, it stopped natural evaporation and the house started to get rather severe damp problems which needed a further fix.

here is a harbour wall, which has been in contact with the sea for a hundred years or so. Observe that the damp is only to the high-tide mark, it does not rise up the wall.

And a warehouse, where the wall has foolishly been coated with a cement render, which has sucked the water to considerable height.

Thank you, that makes a lot of sense!

Does that paint on damp sealant you get from DIY stores do anything? I'm just thinking if we get all the guttering checked and then paint/seal the outside walls by the leaks, we could see if that makes a difference?

if you find the source of the rainwater leak, and correct it, then the wet will stop.

Damp sealant is irrelevant.

I know I must sound like I'm going round in circles here () but if, say, we get the guttering fixed and look outside and we can't see an obvious leak, who is the best professional to call to find the source?

experienced, local, small builder.

It's true about the Parish Magazine.

We had a bit of leak in our kitchen. It was pouring down in and around the window frame.

No idea where it was coming from.

It was actually a faulty radiator in the room above (the other side of the room). The water was traveling along the joist, the full length of the room, hitting the wall and coming down the inside.

Is your bathroom near the leak, or a radiator.

Is there a crack or something in the gutter above?, maybe the guttering is clogged, or the joint between 2 has opened slightly.

Ask you neighbor if they have had the same problem at any time (assuming your neighbours house is the same as yours?

Failing that, Google builders local to you. Prefer small independent ones which have going at least 10 years.

Which are are you (region) - I may know someone reasonably local.

Thank you! All our neighbours are in the same houses so I will go and ask them if we need to. We're in North Herts though, if you are local.

We haven't had the gutters cleaned since we've been in, and we have no idea if the previous owners did, so hopefully it's just them causing a lot of wain on the walls. No bathroom above, and no radiator on that wall.

Have pm'ed you details of my builder as am also North Herts.

Chop, thank you! Much appreciated

Was this mentioned on your survey? When we moved before the few things noticed by our survey were immediately fixed. It might be worth rereading that (if you had one done).

there is something which I think is called a drip channel which is a channel cut into the underside of a stone window cill. This can get clogged with paint if the cill is painted and allow rain water to track underneath and down the house wall where it might find a way in and will certainly make a wall damp. This channel should be scraped clean in any case.

No, nothing on the survey for that part of the house.

Thanks trees, I will have a look for that!

It's definitely rain as it only happens or gets worse when it's rained over the past few days. Dug out the shrubs at the front of the house this weekend and the brickwork does not look healthy underneath!

Now attempting to contact builders and get quotes. Such a novice at this (I miss renting!) so have no idea what's a reasonable cost and timescale for a bit of repointing but hey ho, will fake knowledge so they might think we know what we're going on about!