Where to put the damp proof course here ??

[Heatslave]

Hi ,

Hope someone can help me with this one please ??

In preparation for my new extension, I'm temporarily bricking up this doorway between my dining room and old add-on kitchen. This is so I can knock the old add-on kitchen down (room I was stood in to take pics) and keep the house secure. Do I put the DPC on cement line "A" or "B" ?? As you can see from the pics the bricks either side were drilled and liquid pressure damp proofed about 20 years ago. Common sense to a non builder says "B", but I'd like to know for sure ??

Eventually that brickwork will be cut down the middle(ish) and will be supporting an RSJ, and the wall to the left of the cut will be taken out completely. Do I need to take any precautions to ensure the brickwork is strong enough to hold the RSJ ?? i.e. - tooth it in, use wall ties, use blocks as opposed to bricks, use engineering bricks, etc, etc ??

Hope all that made sense from a non builder ??

 

[23vc]

The dpc should be at least 150mm above outside ground level, if that helps. It would also normally be at or around finished floor level internally. So you need to look at your floor makeup to set it out.
Re the brickwork under steel, any specific requirements should be detailed by the structural engineer.

 

[Heatslave]

The dpc should be at least 150mm above outside ground level, if that helps. It would also normally be at or around finished floor level internally. So you need to look at your floor makeup to set it out.
Re the brickwork under steel, any specific requirements should be detailed by the structural engineer.

Thanks for that. I should be able to find the original DPC under the floorboards, but will still put another one where the drilled bricks are. Just need to know whether I should do it on line "A" or "B" ??

 

[Alastairreid]

Line B from where i stand, but as vc says check your existing levels.

 

[^woody^]

The DPC needs to go below the top of the floor.

And what you should do is build the wall bonded in on one side and straight joint on the other and where the jamb will be, and not have to cut the wall later.

 

[mrgobby]

B for below floor like Woody says, otherwise damp could rise past t and then into anything situated above the floor level that's in contact

 

[Heatslave]

The DPC needs to go below the top of the floor.

And what you should do is build the wall bonded in on one side and straight joint on the other and where the jamb will be, and not have to cut the wall later.

Thanks for that, was thinking the same about the left side, no need to tooth it in

 

[Heatslave]

Do you think a 3-1 sand cement mix will make much difference to the strength of the new wall, as opposed to a 4-1, bearing in mind it's going to be supporting an RSJ ??

 

[rougharsedbrickie]

3:1 is normally found below ground or on your roof

 

[Heatslave]

In the end I decided to get a brickie in to do the doorway. As much as I was throwing cement on the bricks, it was just falling back off !! Know your limits

 

[noseall]

Do you think a 3-1 sand cement mix will make much difference to the strength of the new wall, as opposed to a 4-1

No.

The DPC would go below the course of bricks with the holes drilled in them.