My back door stinks

[Scuzi]

It has been a dry year so far but after the two recent short spells of heavy rain, the utility room to which the back door accesses stinks of damp. Following this with my nose, the offending source is the door sill at one side as circled in the pic below. It doesn’t feel damp to the touch but there is a foul damp smell coming from it.

When the rain stops and after a couple of dry days with a unibond desiccant dehumidifier in the utility room, it disappears mostly. Putting my nose up to the sill it still stinks but not enough to be detectable in the room.

The obvious cause seems to be rain water getting in somewhere. Where do I start to investigate though? This is a recent development; it was never a problem before and there haven’t been any modifications which could have caused a change in the water-tightness of the doorway or surrounding area.

So, before I go picking at my back entrance and possibly making the problem worse, I thought it would be best to get some guidance before causing any further damage. House was built in January 2019 of that makes a difference.

 

[arknor]

I bet your backdoor stinks, sounds like you need to wipe it more often.

pour coloured water on the door and see if any gets inside? silicone sealant any gap?

 

[Scuzi]

Coloured water is a good idea, although on inspection during the rain, there is never any visible water, so I’m guessing it it soaking into the sill from underneath or the side. All of the sealant looks to be in good order on visual inspection.

 

[thezappa]

What is the internal floor finish? Can water enter underneath it?

 

[turbot1984]

*possibly best thread title of the year award.

 

[robfosters]

Thought I’d stumbled across the porno sub forum when I read that title

 

[theone8181]

*possibly best thread title of the year award.

1st response didn't disapoint lol. What's are the walls like around the door? I've found even painted plaster gets a tide mark quite easily from water soaking through. Zooming in, the sealant on the lhs outside looks a bit odd, is it damaged?

 

[Tony Edwards]

Zooming in, the sealant on the lhs outside looks a bit odd, is it damaged?

 

[Mysterae_]

GD Response - it just needs a good bleaching.

Civilised Response - if your house was built in 2019 then the NHBC certificate should cover you for this kinda thing, but knowing how much teeth the NHBC actually has you'd be better off wiping you're backside with it for added cleanliness.

 

[Scuzi]

Glad the thread title delivered. That was the sanitised second attempt

Here’s a close up of the bottom. Is that sealant likely the issue?

Come to think of it, it’s the first time I’ve really had a close up look at it and the finish is pretty poor.

I dealt with the NHBC on a previous house and to summarise, unless the house was at risk of imminent collapse, they weren’t interested.

 

[Scuzi]

What is the internal floor finish? Can water enter underneath it?

That’s Amtico. Laid in December after the whole slab was saturated by a water leak September last year. It was all properly dried out and we haven’t had any issues since. My stomach went into a knot when I first detected the back door leak as I thought we were in for another insurance job, but I’m confident this is isolated to heavy rain events.

 

[Maccapacca]

I can’t see any weep vents / holes. It could be your cavity is saturated and the smell is coming out the shoddy mastic work

 

[Scuzi]

I assume you mean these?

Here’s a close up. The one above the side that stinks is completely blocked with mortar, but it always has been since the house was built. The other two seem mostly clear except a few cobwebs and bits of debris.

 

[BennyC]

I would lift the flooring just behind the threshold and see if the concrete underneath is damp.

My backdoor is not dissimilar in design from yours, heavy driving rain does sometime come through the trim seal on the glazing.

It dries out itself in a few days and has never smelt of damp though.

 

[MissChief]

Thought I’d stumbled across the porno sub forum when I read that title

Every time get close to the post count required to access it they increase it. I think a mod is deliberately trolling me.

 

[hyperseven]

are the drainage holes blocked?

 

[Scuzi]

I would lift the flooring just behind the threshold and see if the concrete underneath is damp.

My backdoor is not dissimilar in design from yours, heavy driving rain does sometime come through the trim seal on the glazing.

It dries out itself in a few days and has never smelt of damp though.

The door did that shortly after moving in but we had it replaced under warranty and so far it seems to be holding the water out.

are the drainage holes blocked?

Quality post! I had no idea those holes existed. I checked just now and they were blocked with dirt and mud, presumably from the bottom of shoes as it is walked over. I’ve given it a good going over with the vacuum and did the test per the video. It’s now draining freely. Whilst down there, I noticed that bit of metal with the drainage holes (Stormguard, apparently) has a bit of dodgy sealant where the stink emirates from. It seems plausible that those holes weren’t draining and the pooling water made its way down the gap. I’ll give it a going over with the mastic gun tomorrow.

To do list:
1. Rip out and redo all of the sealant.
2. Drill out the blocked weep holes (assuming I’m right that they’re the plastic things above the door).
3. Shove a bit of litmus paper from the kids abandoned chemistry set into any remaining gaps to see if and where the water is entering.
4. Bleach it.

 

[teenwolf]

Bleach it

 

[Mason-]

Would recommend CT1 for re sealing.

It seems you've got to the bottom of the problem, but on the weep vents problem, they could be fake. They are a curved L shape if properly installed, meaning if you tried to pull on one of those openings with needle nosed pliers, it shouldn't come out. If they are fake (bodge install), they will come straight out and be doing nothing. I see them all the time on new build snagging videos.

 

[Ayahuasca]

Expected to enter the thread and see a request for bidet recommendations, but left disappointed.