Downpipe Blockage

newbieni

Hi All,

I noticed that the bottom side of my garage has become damp inside. I checked the gutters, they were full of rubbish and the downpipe at the top was completely blocked. I've now cleared it. Would this have caused the damp issue?

Thanks in advance.

WIAWSNB

I know one way to find out

Lorian

Gutter overflowing from the blocked downpipe is most common in that situation. Post photos for more opinions.

newbieni

Lorian said:

Gutter overflowing from the blocked downpipe is most common in that situation. Post photos for more opinions.

I've now included a photo.

newbieni

WIAWSNB said:

I know one way to find out

Wait, I presume?

WIAWSNB

newbieni said:

WIAWSNB said:

I know one way to find out

Wait, I presume?

I was thinking unblock the gutter and DP.
Can you see water overflow from the gutter? 
Or can you see water come out from the downpipe joints? These are not sealed joints, but the top fitting slips inside the lower one. So if water flows freely down them, no water escapes. But if the DP is blocked, it'll fill with water, and this will come out each joint.
Are you DIYish? If you post some pics of the DP, we can guide you on how to remove it for checking and cleaning.

Eldi_Dos

newbieni said:

WIAWSNB said:

I know one way to find out

Wait, I presume?

If the top of the down pipe is accessible to you put down a 5 to 7 metre drain snake with a worm on it  and see if it is clear where downpipe joins underground pipe.

Or if there is a trap clear that out, now is a good time of the year to do these regular maitenence tasks, after leaf fall.

One easy check for to see if a down pipe is clearing ok is give it a few taps up and down the pipe, should sound hollow if all is good.

newbieni

WIAWSNB said:

newbieni said:

WIAWSNB said:

I know one way to find out

Wait, I presume?

I was thinking unblock the gutter and DP.
Can you see water overflow from the gutter? 
Or can you see water come out from the downpipe joints? These are not sealed joints, but the top fitting slips inside the lower one. So if water flows freely down them, no water escapes. But if the DP is blocked, it'll fill with water, and this will come out each joint.
Are you DIYish? If you post some pics of the DP, we can guide you on how to remove it for checking and cleaning.

I've already unblocked the downpipe and cleared the gutter. The top of the downpipe was completely blocked.

newbieni

Eldi_Dos said:

newbieni said:

WIAWSNB said:

I know one way to find out

Wait, I presume?

If the top of the down pipe is accessible to you put down a 5 to 7 metre drain snake with a worm on it  and see if it is clear where downpipe joins underground pipe.

Or if there is a trap clear that out, now is a good time of the year to do these regular maitenence tasks, after leaf fall.

One easy check for to see if a down pipe is clearing ok is give it a few taps up and down the pipe, should sound hollow if all is good.

It's cleared, I unblocked it yesterday, the top was blocked solid.

stuart45

It should make a lot of difference clearing the drainage. That's a fair bit of moisture coming in. 

WIAWSNB

newbieni said:

I was thinking unblock the gutter and DP.
Can you see water overflow from the gutter? 
Or can you see water come out from the downpipe joints? These are not sealed joints, but the top fitting slips inside the lower one. So if water flows freely down them, no water escapes. But if the DP is blocked, it'll fill with water, and this will come out each joint.
Are you DIYish? If you post some pics of the DP, we can guide you on how to remove it for checking and cleaning.

I've already unblocked the downpipe and cleared the gutter. The top of the downpipe was completely blocked.

My apologies - I was looking at your pic on my phone, and assumed that was an external wall, so was searching for the DP...

Ok, water is coming in to the inside of the garage. Your constructions looks very similar to mine - single block skin with pillars, and mine also painted white! Rendered on the outside, I presume? And the render is in good order? 

It's possible that an overflowing gutter, allowing water to cascade down an outside single-skin wall, could allow this, but I don't think it's likely - usual caveats, ext render in good condition, etc. So I suspect it's a rising of the external water level, perhaps just temporarily. Ie, the outside is effectively 'flooded' as it cannot drain as fast as the rain builds it up. Yes, if the gutter/DP/drain doesn't take this away from the immediate surroundings, then the issue will be exacerbated. 

Where does the DP drain to - a soakaway? How far away is it, and how old? Can you remove the DP as it enters the ground? Have you checked the gulley trap there? And if you pour a bucket of water down the gulley, does it drain away?

And, what are the respective ground levels, inside and out the garage? 

Any chance of some photos of the outside of the garage along that wall?

If it cannot be cured the correct way - ie draining away the water, reducing ext ground level, etc. - then you might get some relief by brushing on a tanking slurry, but that would need doing when it's dry, and it's a symptom 'fix' rather than a cure. 

Try brushing and then wiping away as much as possible of that water/damp. Leave the garage door(s) open unless rain is blown in - ventilate it well to get it as dry as possible. Then observe where the water is coming in. If it's come up where the floor slab and wall joins, then expect it to be 'rising' - ie coming in from excessively wet outside ground conditions. Fixes include lowering the ext level, adding gravel drains, etc. And tanking slurry.