DPC for small internal wall on concrete slab

[buffster]

To help with the layout of a new, small, ground floor bathroom, I've had to move a doorway to let me best utilise the limited space available. I've taken about a foot off the wall one side of the door, and now need to build a small wall the other side of the door. This wall will be tied into a wall forming the side of the bathroom and extending into the hall. There is a low beam directly above the doorway, so there are no structural implications from what I'm doing.

I was originally going to build a small stud wall, but am now considering using lightweight blocks instead. There is a DPC under the block wall I've taken a bit off (it's just laid on the concrete slab with the blocks on top), so I figured I should use one for the small wall I need to build, regardless of whether it is of timber or block construction, but my concerns are that if I use timber I would need to pierce the DPC to attach the base plate, but if I use blocks, what stops everything moving as the blocks wont be directly attached to the concrete slab, but to the DPC instead?

Is it simply a matter of using sealant around any holes I make if I choose timber and using mortar either side of the DPC if I choose block? Given that a door will be hung off the wall I'm tempted to try block, especially as it may be easier than trying to secure a stud wall to the beam above.

Any thoughts and input much appreciated.

 

[theprinceofdarkness]

My thoughts are to use heavyweight blocks, tied into the existing mortar courses at every mortar joint. It would be good to get some of the old fashioned DPC material with rough faces. Perhaps some of the smooth stuff and give each side a rough up with sandpaper. Organise some way of sealing it to the original DPC, cut the mortar back by 1", glue up with silicone goo. Bed it down on 2:1 mix with plasticiser so the mix ouzes out. What are going to do above the door, blocks will need a lintel, which also will stiffen up your new "wall".
Frank

 

[buffster]

Hi Frank, many thanks for your reply.

There is a low beam directly above the doorway, so there is no need for a lintel or blocks there.

Why are you suggesting heavyweight blocks? The wall is literally just a spur about a foot long. I was originally going to make it a stud wall, but, after reading a thread here I thought I'd try a lightweight block wall using a wall starter off the existing side wall. The blocks I removed from the other side of the doorway were heavyweight blocks and were far from easy to cut (and created a huge amount of dust), whereas I understand lightweight blocks are much easier to cut. Are lightweight blocks not suitable for this job?

 

[theprinceofdarkness]

If your door frame is self supporting, then lightweight blocks would fill the void. However if the lock side of the door bangs on the frame which is not strong enough, then lightweight blocks will not support it and some thing will give and cracks will appear.
Frank

 

[buffster]

Cheers Frank, I've been away for a few days, sorry for the delay in replying.