Help me diagnose this

[Pappa]

Hi guys.

 

I've got a square patch of damp in my lounge that has just come about in the last month.

Directly behind it is a brick wall that runs adjacent or away from this wall.

Please note the paint peeling under the radiator. The external photo is directly behind this location.

 

The DPC looks to be in good condition outside, although there is a rusty nail in the mortar line which has always been there.

 

This brick wall was constructed in the last 20 years, before I bought the house.

 

Relative humidity is consistently less than 60 percent in this room so I don't think it's condensation.

 

Thanks in advance

 

 

[Pappa]

[Russell griffiths]

What’s that black plastic pipe. 
zoom the picture out. 

[Pappa]

Rainwater pipe from roof.

[saveasteading]

I think this is straight forward.

 

see the green moss and algae on the wall? it is from water running from above. or simply rain hammering into that corner and not running off.

also there appear to be gaps in the mortar.

 

it is above the dpc and getting through to the inside

 

where exactly is the internal dampness in comparison to this external photo? 

 

id have the wall cleaned and repointed. Plus check for water running out of gutters or flashings. You need to stand in the rain to se this properly.

 

You may need to clean out or repair a gutter.

[saveasteading]

the photo is helpful. I suspect a leak from the lower downpipe joints. Notice how the green is spreading out from that.

 

 

 

 

 

 

[Pappa]

Thanks 

I thought so too 

The square patch on the interior is at the external corner or inside the external corner.

 

The paint peels on the floor from behind the radiator correlates to the external picture approximately half way between the vent and the adjacent brick wall 

[Russell griffiths]

16 minutes ago, Pappa said:

Rainwater pipe from roof.

That’s your problem 

fix that and let the wall dry out, then re point it in the spring. 

[Nickfromwales]

Driving rain is pissing in through all the missing pointing. Leave until after April and then sort it.

 

Is the down pipe blocked or do you have any leaking joints? If so fix that immediately. 

[Marvin]

And fill the old waste pipe hole before you get rats!

 

And around the new waste pipe 

 

And any other hole that vermin can enter.

[saveasteading]

I'd scrape the loose paint off to help it dry inwards and also to monitor it. You might find the the plaster beneath shows dampness, and I would mark that in pencil and be delighted to notice that it isn't spreading and may be reducing.

 

Will you be doing diy ? 

Anyway you can brush off the green stuff now, as that is holding water. 

this is one of those queries where we can all feel good at sorting an issue so please repot back for better or worse.

[Pappa]

Thanks guys.

 

Would you advise doing the pointing before spring if there is X days / hours of dry weather forecasted?

How many hours/days would you recommend?

 

How much mortar do I need to rake out and refill?

If you could point me in the direction of a useful guide or video that highlights best practice that would be appreciated.

 

Thanks again

[Russell griffiths]

8 hours ago, Pappa said:

Thanks guys.

 

Would you advise doing the pointing before spring if there is X days / hours of dry weather forecasted?

How many hours/days would you recommend?

 

How much mortar do I need to rake out and refill?

If you could point me in the direction of a useful guide or video that highlights best practice that would be appreciated.

 

Thanks again

You need to consider the temperature for pointing, needs to be 5 degrees and rising for the duration that it will take to dry. 
fix the problem of water hitting the wall first and the pointing can be done in April. 

[saveasteading]

You might simply be able to push up the elbow to stop the leak.

I'd repair the bigger holes ASAP.

A pointing tool is a good investment and disguises my amateur work.

 

 

 

[Roundtuit]

For good measure, I'd also cut the concrete/paving slabs back by 6 inches adjacent to the brickwork and fill with gravel to reduce rain splash.

[Onoff]

9 hours ago, Pappa said:

Thanks guys.

 

Would you advise doing the pointing before spring if there is X days / hours of dry weather forecasted?

How many hours/days would you recommend?

 

How much mortar do I need to rake out and refill?

If you could point me in the direction of a useful guide or video that highlights best practice that would be appreciated.

 

Thanks again

 

You first need to rake out anything loose:

 

 

You can repoint using a hawk and finger trowel. This guy makes a nice job:

 

 

For repointing I like using and have a few mortar guns. I had a Faithful type one but RUINED it by trying to gun a mix that had sharp sand through it. As the chap alludes to in the video, use the proper sand. I can't disagree with anything this he says. For admix I like this:

 

https://www.amazon.co.uk/Everbuild-ILW5L-Integral-Liquid-Waterproofer/dp/B00133HA1A

 

At the mo I've a couple of the slim silver type guns. One branded Roughneck and one slightly shorter tube wise but otherwise identical from Lidl and sold under the Parkside brand as a silicone/caulk/grouting gun! Simply not as good as the Faithful type. 

 

 

[Marvin]

Hi @Pappa

 

On viewing your photo of the rainwater pipe from the roof there is green way above the lower bend of the down pipe.

 

I would be inspecting the gutter down pipe outlet to see if there is any obstruction.

 

Secondly I would also inspect its operation in the pouring rain to see exactly where the problem lies.

 

Me thinks that the problem is starting higher up....

[Onoff]

There's a definite "water course" from above as evidenced by the greenery in the vertical joints. 

[Marvin]

Yes a vertical Wadi.😂

[Nickfromwales]

Maybe a good opportunity to poke an inspection camera in one of the bigger gaps, to look down to check that there’s no masonry that has become lodged in the cavity and is bridging the damp.