Strip or Trench (mass) fill

[dabba]

Only a short while before we break ground with the footings with agreed contractor who will do the footings and oversite concrete & drainage only.

Had a couple of quotes for brick & block, one wants to mass fill the footings and build from there, i'm not sure regarding drains and services ect.

Is there any obvious benefits for just strip or mass fill?  

[nod]

They are really the same thing 

Full fill More money on concrete less on bricklayers 

 

I full filled on our first build Largely due to wet conditions 1800 mil of concrete It made building the foundations for the BB quick and easy 

This time Mainly due to drainage I partially filled 

 

[Dave Jones]

12 hours ago, dabba said:

Only a short while before we break ground with the footings with agreed contractor who will do the footings and oversite concrete & drainage only.

Had a couple of quotes for brick & block, one wants to mass fill the footings and build from there, i'm not sure regarding drains and services ect.

Is there any obvious benefits for just strip or mass fill?  

 

more too it than that.

 

You need to set your finished floor level and work down from there. This will largely dictate what you use.

 

For example, if you are on roughly level ground your FFL/DPC would be around 150mm above that. working down:

 

screed - 75mm

insulation - 300mm EPS

Beam - 150/225 depending on spec

brick to sit beam on 75mm

trench block to give 150mm clear space below the beam 225

 

so as a bare minimum you are into the ground 675mm already and this assumes your drains work with this.

 

So a 1m footing would only give you 325mm of conc which wouldn't be much, BCO like a min of 600 which now puts you at 1300 into the ground etc.

 

It's a cost equation between muckaway vs conc cost etc

 

 

[dabba]

55 minutes ago, Dave Jones said:

 

more too it than that.

 

You need to set your finished floor level and work down from there. This will largely dictate what you use.

 

For example, if you are on roughly level ground your FFL/DPC would be around 150mm above that. working down:

 

screed - 75mm

insulation - 300mm EPS

Beam - 150/225 depending on spec

brick to sit beam on 75mm

trench block to give 150mm clear space below the beam 225

 

so as a bare minimum you are into the ground 675mm already and this assumes your drains work with this.

 

So a 1m footing would only give you 325mm of conc which wouldn't be much, BCO like a min of 600 which now puts you at 1300 into the ground etc.

 

It's a cost equation between muckaway vs conc cost etc

 

 

Thanks Dave,

I'm tight on levels for drainage, not be using beam& block. drawings show  "150mm hardcore, 50mm sand, 100mm ST2 or Gen2 ground bearing slab, dpm, 150mm celotex or similar, 65mm sand & cement with light mesh reinforcement" strip footings show shown as 600mm x 225mm at 900mm depth (building inspector wants to see good ground conditions when footing dig starts) 

[markc]

If no DPM between hardcore and slab then no need for a sand blinding layer

[Canski]

I have just excavated 1m below ground level and filled it to 600 mm below ground so 400 mm of concrete and LABC and the warranty inspector were happy with that, then had 375mm to the underside of insulated beam and block then 300 mm of beam and insulated block leaving 75 mm for cemfloor screed over the top to DPC. Like Dave says work from the top down. 

[dabba]

1 hour ago, markc said:

If no DPM between hardcore and slab then no need for a sand blinding layer

It should have read 150mm hardcore, 50mm sand, DPC, 100mm concrete sub floor, insulation 150mm, 65mm screed.