Removing a block from wall, and refitting.

[Dazza Jones]

I am trying to trace the cause of a damp patch on my external gable wall. It is on the 2nd floor, pretty much where my en suite shower was.

I had been advised to remove a brick and inspect. This would involve scaffold/access equipment.

The en suite shower has now been stripped out to the block wall.
Is it possible to remove one of the larger blocks from inside the house, instead of messing around outside, or is that a really bad idea. Will my house fall down around me? Is it a DIY job?

The idea is to remove it, check out whats going on inside the cavity, and replace.

Hopefully there is an attached picture of the block wall in question, where the shower used to live.

 

[DIYer Damo]

Hi Dazza,
I would say removing an internal block is easier than external brickwork and when you put it back in your mortar joints won’t need to be as neat / matching.
If you’re removing just one block you should be fine but any more than that you might want to think about supporting the wall in some way.

 

[Dazza Jones]

Thanks Damo,
I will only be taking one out at a time, but will prop the gap during the time the block is out anyway.
I have been looking into buying a spare block just in case it gets damaged, but 610x210 (approx) doesn't seem to be a common size. Im hoping it will be 100mm thick.

The missus is now going spare saying the house will fall down. Maybe she knows something I don't.

 

[oldbutnotdead]

1 block out will be fine, best if you stitch drill the mortar out (or if you can live with the mess, use a diamond disc in a grinder to start with) rather than laying into it with a hammer and chisel.

 

[Nozzle]

Or use a mortar rake that fits into an angle grinder - less mess than a cutting disc as it doesn't go as fast at the cutting edge.

Nozzle

 

[Dazza Jones]

Thanks guys.
The game has changed slightly as I have now found that the cavity is full of the white ball type insulation.
I'm trying to come up with a plan to remove the block, stop the million insulation balls filling my bathroom, then refit the block and insulate behind again.
Right game. ...

 

[Tigercubrider]

Would it be possible to drill around the block and use squirty foam to hold the balls in place?
Or would that bridge the cavity?

 

[Footsoldier888]

Just throwing this one open to people that know the answer - is the advice the OP has received about taking this block out the correct advice? I mean checking a cavity normally entails drilling a small hole and feeding a camera down.

Given that a broken seal on the shower tray is a likely suspect for causing this damp does the block need to come out??? Just asking.

 

[oldbutnotdead]

Just throwing this one open to people that know the answer - is the advice the OP has received about taking this block out the correct advice? I mean checking a cavity normally entails drilling a small hole and feeding a camera down.

Given that a broken seal on the shower tray is a likely suspect for causing this damp does the block need to come out??? Just asking.

You have a point about the likely cause- that block wall looks very salty near the bottom. Not sure how well the camera bit would work with poly balls in the cavity, might be worth a go. But get a decent camera- my cheap one from CPC isn't as steerable as you'd need for a job like that

 

[Ian H]

You could saw half a block out with a normal saw.

 

[KenGMac]

Is the cavity filled with a retro-filled cavity insulation?

If so the singular damp patch could be down to cavity bridging where a wall tie has a load of mortar lying on top of the wall tie allowing water to pass between the inner and outer leaves of the wall?

Damp issues such as damp spots internally are often down to poor retro-filling of cavities with insulation, fibrous blown insulation is well known to lead to such issues.

Ken.

 

[Dazza Jones]

I feel i should rewind slightly for reference.

I 1st noticed the patch on the external wall around Christmas time, and took a picture underneath. i made a thread on here:

https://www.diynot.com/diy/threads/dark-patch-on-external-wall.496219/

ive since taken a picture from a different location which shows two patches.

The chimney is fake and is a concern, as it is so high. I have checked inside the loft and have no damp.

We had a damp guy round who advised we take a block out to see what was going on as he wasn't sure where the patch was coming from.

I have drilled a few holes in the mortar of the block wall in varoius spots and put a cheap camera in that i already had. the areas where the tray sat shows signs of wet especially in the corner, higher up was dry.
What is confusing me is the higher of the damp spots outside.

The cavity insulation has not been retrofilled.

I currently have a dehumidifier in the bathroom and the prevoiusly wet spot holes are drying, but im not 100% convinced the problem is solved (as in, i dont know if its the chimney!)

 

[tomfe]

How long have you let it sit for to dry out? With the weather it should not take long.
Make sure it's water causing the damp and not a stain on the brick work.
For the outer skin to become saturated from an internal leak is unusual.

They are Durox blocks but any aircrete block will do but you'd have to cut a couple down.

 

[Dazza Jones]

The shower hasn't been used for about 6 weeks now, and has been removed for about 4 weeks.

How long would you say it would take to dry out? The patchs outside dont change in size at all.

The other maybe is the false chimney. If that was letting water in some how maybe it's running down the cavity, but I would have thought you would see the damp all the way from the top.

I am slightly losing my way with it now I think. I have had a builder and a damp proof guy and neither really had any answers.

 

[Footsoldier888]

Maybe this is the new version of crop circles .