mortar joints

Can anyone help please. I have had lots of emails about the dpc cavity tray. The only thing is when I remortar the joints on the horizontal cuts between the bricks, do I just fill it with mortar? or should I pack the joint in places with slate or similar as well? The cuts will be 2 metres in places. Many thanks for help. Neil

Has anyone got a clue as to what this is about ? I have got a vauge picture but what's the goal?

Alex

How are you going to remove a whole mortar joint without the bricks above it simply falling and closing the gap? Or are you expecting to do it in short sections. In which case how do you install a continous DPC?

Well if mortar was good enought in the first place it ought to still be.

Is there not some other way of closing the access to the cavity?

Well make sure that you don't do it upside down. Remember to trim too.

I'd challenge the BCO on the reasoning behind this. I dont understand why this would be required on a lean to ... get him to quote chapter and verse.

My builder mate has some things to say about a BCO or two ...

Alex.

IIRC it's one of the requirements in the Building Regs (They're online

- google for them including the term "odpm"). From memory (and assuming I understand the physical arrangement of Neil's building correctly) the logic is that it stops rain penetrating down the upstairs outside wall and into the inside below IYSWIM. Sort of rising damp but the other way up.

Neil, something you said worried me a bit, I hope I'm not too late. I think you really need to allow the new mortar to set properly in each short section before you start on the next. I know it will make the elapsed time for the job much longer but I can't see how the wall will stay up otherwise! I'll let others here with more knowledge and experience than me define "set" in this context, I find that mortar is still soft a day or so later and only really hardens properly over a week or so.

What I still don't get is: is this inserting DPC or a cavity tray. If the latter I can't understand how this would be done by chasing mortar sectionally from the front if the tray is to bridge and seal the cavity.

If its just DPC then I get it.

I have not looked on ODPM for this, but regs apart I don't get why you would need to put a cavity tray in where you are essentially chasing out some mortar to put a flashing in above the tiles ??? Have I got the right mental picture? Surely once sealed this is just as good as the original mortar?

Alex.

If you are being a bit crafty you could probably do a section, leave a gap, another section, leave a gap etc. Then once those have set go do the gaps mext time!

Useful link:

Also, you can often treat the wall above the wall-plate with a water-proofer. That may satisfy the BCO. Simon.

AlexW wrote: >

Aha ... have it from link in other part of thread.

Alex.

Here's another advice source:

That's what my BCO required. It was a few years ago. How long does the silicone water repellant last? Will it need re-coating?

Why not do alternate sections first(as when underpinning) and do the remaining the following day? Mortar should be hard enough by then, unless it's a very wide opening, as it's only a triangle of bricks supported.

Thanks, I didn't know posting was so involved, I will try to improve my replies etc. Neil