Where is this water coming from?

[brendak]

Hi
We have a glass & metal front door. Recently I have noticed a water stain on the wall just inside the door.
Could anyone advise where the water is getting in?
Thanks

 

[Paul Cumbria]

The first thing to check is the mastic or sealant around the door frame. Even the smallest gap will allow water ingress; I used 5 or 6 applications of Sikaflex sealant built up in layers to make sure there was a good seal. If the wall is of solid construction water can soak straight through the stone/brickwork, especially through the mortar. With a cavity wall, water pools up on the part of the doorstep behind the frame, soaking through the mortar on the lower brick course. There may also be rubble etc piling up on that bit of the step, which will assist water migration, and hinder drying - ditto for anything bridging the cavity at whatever height. This may have been going on for years before it becomes obvious, so if you have wooden floors, I would recommend checking on the floorboards and joists underneath if possible.

 

[Mike1221]

I would check the attic, too, just to make sure the water isn't coming down the inside of the wall and soaking through.

 

[Paul Cumbria]

Check also the threshold - there will be a strip of wood or metal across the bottom of the door opening. I thought I had sealed mine (PVC) after a lot of effort 18 months ago, only to find it is leaking again after the recent storms due to the sealant cracking. There will be a lot of movement due to thermal expansion and contraction, so any sealant will crack and split in time so a good flexible sealant is needed. I will have to re-visit mine yet again when the weather is drier, so have just bodged a temporary seal for now. This can happen for years without being noticed, causing damage to floor boards, floor coverings etc.