Help, rain is penetrating my conservatory wall

[Suzcooke]

it is raining heavily and I can see that where the single skin brick wall of my "lean to" meets the concrete floor water is seeping through as I have wet patches appearing.
There is no actually pooling of water more like the water is soaking through and the patches are slowly getting larger.
Any ideas how I can deal with this?
I was thinking of waiting till it dries out and using a brick stabilising solution but have no idea if that's a good idea

 

[Doggit]

Sorry for the problem, but we'll need a picture of the outside as well. Brick stanilising solution won't achieve anything I'm afraid.

 

[Suzcooke]

Thanks for responding, I've just popped outside and took a couple of pics

 

[Doggit]

firstly, you've got the wrong type of gravel in the french drain; you need stones that are at least an inch in diamater, and prefereable 2. Dirt has filled the gaps, and is allowing the water to travel across. Do you know where the DPC is - and in relation to the height of the ground outside.

 

[Suzcooke]

Hiya, I had a look this morning and couldn't see any sign of a dpc but I'm planning to dig out the trench over the weekend and hopefully unblock and re-gravel it.
To be honest the various building work done by the previous owners is a bit shoddy so I'm considering the possibility that there may not even be a pipe installed although I am obviously hopeful.
Can't thank you enough for your input and advice and I will let you know the outcome

 

[garyo]

dig out the trench over the weekend and hopefully unblock and re-gravel it.

Have a good dig down to establish your DPC level and take another photo. It's not uncommon that pathways and patios are laid too high and cause problems like this. Do you already have a sense of how the outside path level relates to the inside floor level?

 

[Suzcooke]

Thanks for responding Garyo

I have a feeling that they are a very similar level but will deffo update and provide a pic at the weekend.

If there's no pipe in the trench can I just improvise by digging deeper and filling with large gravel or by drilling some holes in a piece of plastic drain pipe?

The trench is less than 4 foot long and I have only seen large lengths of perforated tubing available online

 

[garyo]

Chances are your DPC level is at about the same level as your internal floor level. The external floor level *should* be 150mm below this to deal with rain splashback off the path etc.

In reality, what you can get away with will depend on a variety of factor: is it on a wall that faces the weather and driven rain.... is the path well sheltered under a big overhanging soffit, or directly exposed to rain under a bare gable end? If it's a single story wall then that will shelter more from the weather than double due to any roof overhang being closer, as would a garden fence two feet the other side of it.

The gradient of the path and surrounding garden will also come in to play.

I'd dig out the gravel channel to establish where DPC level is, and probably leave it clear for a few months given that we're heading in to summer - give it a chance to dry out. Then when/if it does rain you can pop out to take a look at which way the gradients are working and how much flowing water the channel needs to deal with. A perforated tube may well work if you really don't want to lower the path, and is cheap enough to give it a go. Have you tried looking for an off-cut on eBay?

 

[Doggit]

A french drain as they are called, doesn't have a pipe at the bottom of it. What it's doing, is keeping a gap between the path, and the wall, and stopping any water build up getting into the wall above the DPC. Most people make the mistake of putting in gravel, and that fills with dirt, and the water tracks across. Now it can still happen with large stones, but it'll take a lot longer to fill up. It should go down at least 6", and as long as you haven't got so much water going in there to cause it to overfill, and the earth at the bottom can handle the flow, then you don't need to worry about putting a drain in the bottom.

 

[stuart45]

A modern French drain has a pipe at the bottom, but it needs to drain somewhere away from the building. The original French drains were just trenches filled with gravel, but they still drained away the water.
The one in the photo is probably just a trench with stones not draining away to a soakawayetc.

 

[John D v2.0]

In this case the op needs to determine if the penetration was caused by the channel filling up, splashback off the path, or just the stones being higher than the dpc and it running down to the inside. The correct course of action would depend on that answer

 

[Suzcooke]

All your responses and advice are very much appreciated.

I had a little dig around last night in the relentless rain and it seems there's lots of silt and debris etc down there so it's hardly surprising the water isn't draining away.

The area does not suffer from driving rain as I have my wheelie bins in front of the wall.

It's the surface water running off the patio that seems to be the most likely cause of the problem.
Looks like I have my diy job for tomorrow planned out (lol)

I will update and post pics during the process, thanks again

 

[John D v2.0]

I should have added to my list that it might not be related to the ground at all, it could simply be water running down the wall and tracking through above the damp proof course, although that does seem less possible than the other options. More likely in a cavity wall with a bridged dpc than a single skin wall.

 

[Suzcooke]

Well I've dug out the gravel and the trench is very shallow, maybe a few inches max and the base seems to be concrete and not earth as I cannot dig down past it, there also doesn't appear to be any visible dpc.
The area all around is patio slabs so I'm not sure where the water is supposed to drain to
Is it really worth filling with large size gravel or could I just put something over it to stop it getting full of water as it is hidden behind my wheelie bins?

 

[Suzcooke]

Ops forgot the pic