Have I buggered up my brickwork already?

[pilsbury]

As you may or may not know, building a single storey side kitchen extension. Bit of a novice and finding my way with some great help from here.

The build has 3 levels of DPC. 2 levels are original. The main house DPC is 1 brick below the extension DPC. The garage DPC is 3 bricks below extension DPC. As I discovered on here and my building control guy informed me, the way to tie them all in is to cut a channel in the original DPCs, mortar the new DPC in, run it vertically up the wall and then continue this on to the new brickwork.

The other day in preparation for my bricklaying, I duly cut channels into the old DPCs. Next day got cracking nice and early starting laying bricks. Spent an age setting out then got into my groove. Chuffed to bits to finish the outer skin to DPC level and pointed up all nice. Next day go to inspect my handy work and see I have forgotten to insert the DPC into the old DPC.

Just outer skin done so far and I wonder how much of a balls up this is? What can be done? Does anything need to be done? Can I just lay DPC on top of my new outer skin bricks? Will it be OK just to do the inner skin properly? FYI the bricks are old imperials that have the appearance of engineering bricks (hard as nails and slightly shiny outer face) and I guess should be pretty water resistant and frost resistant

 

[pilsbury]

Is it considered rude to bump this? - really could do with some experienced thoughts....

 

[CJRatch]

Not an experienced thought but a logical one is that so long as your cavity is clear at DPC level the only problem which isn't really a problem is damp may travel above the DPC line on the external skin. If your cavity is clear any damp above the external DPC wont spread onto the internal skin so won't cause you any internal damp problems.

Plus if as you say they may be engineering brick damp won't travel through many courses anyway so depending how many you have up to DPC so may have gotten away with no DPC at all.

 

[^woody^]

The external leaf wont matter, as you have a cavity. If you wanted to, the mortar will be still soft enough to recut the slot with an old saw and lap some DPC into it.

For the inside you can lap it or turn the DPC up the wall for about 300mm or so

 

[pilsbury]

Might consider the saw cut - been a few days now. On the other hand, as you suggest, the inner skin is more important and I've not built that yet. I will ensure I don't zone out on that build and get it in properly.

Just to note, the extension is obviously cavity - the old house is solid 9" wall. So there might be the chance the moisture could travel up my extension wall and traverse across into the old 9" wall above DPC then across..... Likely? Seems feasible but pretty unlikely. I'm 3 bricks above ground to DPC

 

[^woody^]

The text book way is to cut a slot and insert a vertical DPC wherever an external wall becomes an internal wall.

But in practice it would take a lot of direct rain for moisture to cross a solid 9" wall. If you are not forming a vDPC, then if there is ever a problem in the future, you can brush some clear water repellant on to the old external wall at that location

 

[pilsbury]

Thanks Woody. A very simple solution and reassuring. With luck, my bricks will be my saving grace - as I previously mentioned, they are hard as nails, very dense and have a satin finish that strikes me as very water resistant/repellant.

Now to take this lesson on the chin and keep my head engaged when I do the rest.