Damp bricks on an outbuilding

[Beginerz]

Hi all.
We removed a conservatory and it's concrete slab base from this spot around Christmas time.

No sign of damp bricks on the outbuilding at the time. About 6 weeks ago a water company engineer who was examining the sewer which is outside the back door, off to the right of this photo, asked us to turn on water supply and flush the toilet in the outbuilding. The toilet is located to the left on this picture on the inside of the building, probably where the second brick in and the damp brick meet.

Appears damp can be seen under the damp bricks too.

Anyone know what could be going on here?

We have suspicions regarding that toilet being there. It hasn't been flushed since and we've turned the water supplying it off again. There is still some clean water in the toilet basin.
Or could we be looking at some kind of rising damp?

I'd say as recently as early March the bricks were unmarked. Happened since then.

 

[blup]

Not clear where the sewer pipe runs, but could be a leaking water supply pipe, possibly disturbed when removing tne conservatory/adding the new slabs

 

[Beginerz]

Blue line indicates where fresh water supply comes up from the ground. It then goes over the outhouse door towards the toilet internally and then into the cistern. We are the first house on the sewer run and it goes off in the direction of the red arrow. However there is a waste pipe coming into the sewer from the adjoining property which runs under the line of slabs seen on the right here. However the pipe is at least 1.5 feet below the level of the hardcore you can see.

I removed the concrete conservatory slab myself and didn't see any pipe coming from the toilet direction. I only broke away slightly below the hardcore level you can see now and just topped it up slightly. I would have thought that pipe from the loo would be lower than that though?

It could be that the waste pipe from toilet to sewer was damaged to begin with and flushing it when the drainage engineer asked has forced water from the pipe. But I wouldn't have thought one flush of clean water about 6 weeks ago would cause what we can see here? It hasn't been flushed since then.

 

[blup]

If its not a damaged pipe, then possibly damp coming through from under the slab inside the outhouse especially if this doesn't presumably have a dpm. The finished floor level is at or above the top of the dpc.

 

[Beginerz]

The finished floor level is at or above the top of the dpc.

Is that as it should be or ideally not? I believe it's still as built in the 1960s and the whole estate has outhouses same design.

 

[blup]

Is that as it should be or ideally not? I believe it's still as built in the 1960s and the whole estate has outhouses same design.

If there is no dpm under the slab the damp rises through the floor and bridges the dpc, albeit isolated in your case. Damp can appear in some areas and not in others even though the same conditions apply. Probably best to observe it over the next six months or so.

 

[Beginerz]

If there is no dpm under the slab the damp rises through the floor and bridges the dpc, albeit isolated in your case. Damp can appear in some areas and not in others even though the same conditions apply. Probably best to observe it over the next six months or so.

Oh I see.

It does seem very strange it should appear so suddenly and especially as it was once we allowed water to supply the toilet cistern for the first time since buying the place and flushing that loo.

Might it be an idea for us to dig down on the outside and see if we can find anything?

My other half wants to get the toilet removed and waste pipe capped off from the inside. I'm keen to pave the rest of that hardcore'd area but am cautious as I assume covering up some of that damp is just likely to stop us knowing what's happening.