DPC or Emgineering bricks for new extension?

[gasbusters]

Hello all. Was hoping to get some expert advice over a slightly confusing issue.

I'm going to be building a kitchen extension and gym, the kitchen extension will be 5 meters long by 4 meters wide. The gym will be 3 meters wide by 5 meters long.

My question is to do with the plastic DPC strip or membrane that's placed on the wall about 150mm up, running along the full length, with bricks and mortar placed directly on top of this. This to me seems to create a barrier between the bricks below and above the membrane, which means there could be a possibility the wall could "slide" as its not directly mortared to the bricks below.

My neighbour recently had his extension built and this is the method they used and I can't understand how that's the safest means to build a wall.

Now my gym will have two 8x3 inch wooden beams running along the top of the wall to support 2 large punchbags. These will be used regularly, so I'm concerned the vibrations on the walls from the punchbag use could potentially cause sliding or movement of the walls if they are not directly mortared (ie. If there's a plastic Dpc at a low level.of the wall)

Could engineering bricks be used instead of the DPC strip and if so would this provide the same level of protection against rising damp?

 

[jks7492]

No your punchbag is not going to cause the wall to fall over. All modern houses are built with a DPC like this and it is not an issue

 

[Jake2021]

Both use dpc and engineering bricks first 2-3 courses

 

[Jake2021]

What size are those motar joints seem a tad.thin on photo

 

[gasbusters]

What size are those motar joints seem a tad.thin on photo

Imguessing around 10mm? That's my neighbours extension

 

[gasbusters]

No your punchbag is not going to cause the wall to fall over. All modern houses are built with a DPC like this and it is not an issue

This may seem VERY unlikely but how would these homes react if a relatively powerful earthquake hit? For arguments sake?

 

[Jake2021]

They should.be 10Mj they look thinner but could just be angle of camera

 

[Jake2021]

With earth quakes.It's foundations that go not.the brickwork.I understand what you mean 're dpc but it is safe just make.sure you have a decent bed below.it.and it's fully pressed down... It's less safe not to put.it.in , it wouldn't get signed off if.not safe

 

[mikeey84]

This may seem VERY unlikely but how would these homes react if a relatively powerful earthquake hit? For arguments sake?

A house wall is not going to slip off the dpc during an earthquake. If there is lateral movement, much more likely the wall will fall over from the top.

 

[^woody^]

Looks like every house built in the last century is a slide risk! But are damp free.

 

[Notch7]

Now my gym will have two 8x3 inch wooden beams running along the top of the wall to support 2 large punchbags. These will be used regularly, so I'm concerned the vibrations on the walls from the punchbag use could potentially cause sliding or movement of the walls if they are not directly mortared (ie. If there's a plastic Dpc at a low level.of the wall)

Could engineering bricks be used instead of the DPC strip and if so would this provide the same level of protection against rising damp

You are right, returning the DPM over the DPC does introduce a slip

But the inner course is attached to the outer course by brick ties and the outer course has a DPC which is patterned to drip the mortar.


Funnily enough DPCs can slip - I rented a factory made of extra thick concrete blocks, a skip lorry reversed into a section next to some roller doors - the whole wall, 4 metres high moved about 2 inches on the DPC.

 

[cdbe]

Quite handy if you need to move the extension or the house, you can just slide it onto a lorry like they do in America.

 

[Dereekoo]

Interestingly my neighbour had a front brickwall with a plastic dpc strip incorporated in it and the hedge at the back of it had pushed the wall out by about 8mm. I believe the totally correct way to incorporate a DPC into a strucure is to butter both sides but obviously with a block like structure this nicety is ignored.

 

[johnny2007]

Get a damp proof tray installed as well.

 

[stuart45]

Interestingly my neighbour had a front brickwall with a plastic dpc strip incorporated in it and the hedge at the back of it had pushed the wall out by about 8mm. I believe the totally correct way to incorporate a DPC into a strucure is to butter both sides but obviously with a block like structure this nicety is ignored.

A Plastic DPC shouldn't be used in a garden wall, only 2 courses of engineering bricks if required.