Beam and block disctance

[Zehroni]

trying to fit beam and block flooring to rear extension. the floor level of the extension must be in the same level as the existing building. all I can see from the back wall of the extension is the DPC. How far down I need to install my beam from the DPC to allow the following:

100 mm insulation
75mm screed to cover the underfloor heating
10mm for floor tiles

this height of the beam is 150mm

 

[acurachris]

Assuming your internal floor level is the same as the DPC, then you'll need to work down with your measurements, so 175mm screed and insulation plus 150mm beams, means the beams need to sit at least 325mm below DPC.

In your case the height isn't going to fall inline with the brick courses so you'll either have to go further down to the next brick row or use coursing bricks to make the desired height you want. Better to install the beams lower than too marginal as you can always lose the extra height in additional screen or insulation. Set the beams too high and .... oops!

What is your internal leaf constructed with, brick or block? Does your foundation allow you to go that low?

 

[noseall]

You will have a DPC under the floor beams as well as one at floor (top of the screed) level.

Your beams therefore will sit 325mm below DPC. The tiles or any flooring material should be irrelevant. It is the screed level which needs to match through.

 

[Zehroni]

I managed to drill a hole 3cm above the DPC from outside (just to make sure that I am coming above the floor from inside).
the distance between the hole and the DPC is 3 cm from outside
and the distance from hole to the laminating flooring inside is 7.5cm. therefore, the laminating flooring is 4.5cm below the DPC. add 8mm laminating and approximately 4mm underlay. the internal floor board is 57mm below the DPC. is this I need to go 57+325 below the DPC..... correct?

 

[Notch7]

I managed to drill a hole 3cm above the DPC from outside (just to make sure that I am coming above the floor from inside).
the distance between the hole and the DPC is 3 cm from outside
and the distance from hole to the laminating flooring inside is 7.5cm. therefore, the laminating flooring is 4.5cm below the DPC. add 8mm laminating and approximately 4mm underlay. the internal floor board is 57mm below the DPC. is this I need to go 57+325 below the DPC..... correct?

Sounds about right. Personally I prefer to use a laser level to set datums these days -if there is an open window or door to shine it through.

Can you check in more than one place? Its always best in case the existing floor slopes a bit.

Ps tip: nobody uses cm's (always mm's or m's)

 

[Zehroni]

good idea , I have spirit level with integrated laser beam on a tripod, I will shine it through the conservatory door to double check

 

[noseall]

We always knock a hole through (in positions of any knock-outs) and use a level onto any screeds or floor-boards.

 

[^woody^]

If the new floor needs to be level with an existing, then there must be a doorway to connect the two. Knock a hole through.

Put a level across, measure down with a tape.

 

[noseall]

If the new floor needs to be level with an existing, then there must be a doorway to connect the two. Knock a hole through.

Put a level across, measure down with a tape.

That sounds like a good idea woods...….

 

[^woody^]

That sounds like a good idea woods...….

I thank you.

I've patented it, so don't get any ideas.