Beam and block floor

[Pete57]

We are currently having a side extension built by a builder who came recommended by a friend.

New blocks have been laid to the height for the beam and blocks on the new foundations and bricks have been knocked out of the existing house wall in order for the beams to be put on.

My concern is where bricks have been knocked out the beams that I can see are either laying on old mortar or propped up by a brick as per photo. Is this standard procedure? Any help is greatly appreciated.

Untitled

• Pete57
• 10 May 2013
• 1

Untitled

• Pete57
• 10 May 2013
• 1

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[Joe Malone]

The beams should be laid at either end on a supporting wall and ideally should be laid on a DPC. They don't need and shouldn't be propped and I'd strongly recommend that they are not laid on old mortar as this may crumble under the weight resulting in an uneven floor further down the line.

 

[Pete57]

Thanks Joe. It is a supporting wall. They tried to tell me the brick was just to help with level. Should they be taking off the old mortar and bricking to the correct level properly?

 

[Joe Malone]

Yes, sounds like they know the mortar isn't up to the job and are propping in case the mortar fails. If the end supporting wall isn't at the correct height then they should be packing it properly with slate or something else more suitable.
Also doesn't look like its been laid on a DPC?

 

[theoldun]

Should they be taking off the old mortar and bricking to the correct level properly?

Yes beams must always be bedded on solid brickwork to the level required.
No packing ever under beams
We always run a DPC under beams and a 300mm wide DPC above beam with 200mm lapping block and beam so that visqueen can lap over.
Regards oldun

 

[Joe Malone]

No packing ever under beams

Regards oldun

Agreed, this is the ideal but pragmatically, if the floor is level now then removing the old mortar means the floor will run out and you will be looking at either rebuilding new walls to a height that matches existing or packing the beams.

 

[Pete57]

Also doesn't look like its been laid on a DPC?

They told me a DPM goes on top, then insulation and then screed.

 

[Joe Malone]

It needs a DPC. Just do a search on google images for block and beam construction and you'll see lots of images showing the construction detail.

 

[limerockconstruction]

DPC definitely required, but I also thought that there was meant to be 150 minimum air gap underneath as well. Also make sure it's been ventilated.

 

[jeds]

Minimum void beneath beams is 75mm. All looks a bit rough to me. Can you post a photo of the overall floor?

 

[Pete57]

Brick layers are here today. The beam in the picture is only temporary until a soil pipe from the toilet is re done. The brick layers will then make good this wall for the beam to lay on so hopefully all good.