Damp Patch On Garage Floor

[securespark]

We have had a damp Patch on the garage floor for a good few weeks now.

It's right near an incorrectly fitted PVC door (IFD). The door has been like that since we moved in in June 1999.
I thought there might be water getting under the door, but I sprayed a hose under there for 20 minutes and nothing came through the other side.

Next to the damp patch is a washing machine but there's no sign of leakage there. Besides, the damp patch does not spread that far, on the surface, at least.

But outside, next to the IFD is a drain that has been added to over the years and is overcrowded.

Sometimes, I go outside and see that water has overflowed from it. The edges of the pottery are crumbling and I'm wondering if water is leaking into the surrounding ground and up through the concrete area inside the IFD.

Is this remotely possible, or am I being daft?

The WM is just to the left of the damp patch behind the ply panel.

The IFD is just to the right of the drain.

I'm wondering if I should lift a flag or two and see if the drain is broken, or try to find out why the ground underneath the flags is saturated.

 

[JohnD]

Glazed clay pipes and gullies are, IME, always cracked or broken and leaking, usually at the trap or the bend where they turn from vertical to horizontal.

However my experience has mostly been in houses on London clay built before 1945, which were generally subject to movement and ground ripple, as well as settlement. Old water pipes also leak under floors. Your house looks newer so may be different. The water may be rising up that crack from beneath the concrete floor. If you know a young person with good hearing they will detect the noise from a pipe leak stopping and starting when you turn the outside stopcock off and on.

I can't see the DPC in your pic.

 

[securespark]

In the floor or wall?
We are on clay in this part of Stockport.

The main house is 1960, but the extension where you see the drain is 1994 and the concrete in the garage and the extension above is 1970.

 

[JohnD]

I was looking at the wall

 

[securespark]

Near the drain?
I'll have a look tomorrow.

 

[JohnD]

BTW, patched concrete and mortar poultices are often found near leaking drains, signs of past futile attempts to fix them without digging them out (which is always necessary)

 

[securespark]

Have edited the first post.
I'm sure it's clear but made it clearer.

The damp has only recently arrived, it's the door that has been like that since we moved in.

BTW, talking of DPMs, should the garage floor have one?

 

[JohnD]

Older garages often had plain concrete floors. Even if the damp evaporates off unseen, you tend to get condensation damp under mats or objects placed on the floor.

Modern concrete floors tend to have plastic DPM. Often, as in mine, you can see it projecting at the edges in a garage as there is no skirting orplaster to hide it.

 

[JohnD]

Washing machine waste leaks tend to leave white stains from the washing powder. Bath water can have traces of soap or foam.

Water pipe leaks are very clean but tend to leave cavities where they have turned the ground to mud and washed it away.

Soil pipe leaks can give you wild tomato plants and prolific red worms.

 

[securespark]

Thank you.

I'm guessing whatever the problem, that drain/ gulley needs sorting as it looks inadequate for the number of pipes running into it.

 

[securespark]

Sorry for the delay....

I've got some pictures now.

This is the 1994 extension just to the left of the drain.

Then there is a vertical membrane between the 1994 extension and the 1970 garage extension.

Then there's one on the 1970 garage extension.

 

[JohnD]

I can't make out what the 1994 extension pic shows. Is that a mortar fillet to paving?

I see the the DPC above it. (Ed.)

Can't see any damp patches in the brickwork in those pics. The DPCs look OK

 

[JohnD]

Is the door sill near enough to the ground for rain to get under it? Or when the gulley overflows?

Plastic doors and windows have moulded-in channels for rain to escape outwards. Yours aren't draining in, are they?

 

[dilalio]

Stick some drain dye in the gully.

 

[securespark]

Thank you, people!

The door, as previously mentioned, is inside-out....

The sill is on the inside, believe it or not!

But I have spent an hour with a hose at full flow outside aimed at the bottom of the door and nothing has got through to the inside where the damp patch is.

As the door is inside-out, I guess, those drainage channels would be on the inside?

Drain dye is a genius idea.

If the water is coming from the gully and up through the garage floor, if I put dye in the water, would it colour the floor?

I'm not worried about that, I just want to know if it would be strong enough to show up.