Beam & Block - Ropey beams?

[Mulberry View]

So, day one of DIY installing our Beam & Block went well. I've managed to get most of the 40 beams in my Living Room area in place. This is being done with no machinery, all beams are inside the perimeter, which is a blessing and a curse!

 

To note, our beams are 175mm deep and are ALL spaced at 275mm centres, due to my paranoia about floor bounce. Longest span is 3.9m (the ones in the photo are around 2.85m).

 

 

What's the expectation with the beam standards? My beams all look to have been cut by Stevie Wonder, none of the ends are straight and some have chunks out of top/bottom surfaces.

 

As part of a change of building tact, I had to cut around 100mm off almost every one of the 180 beams in my scheme, which was no fun, but this allowed me to cut the damaged ends off, so that's OK.

 

However, now that I'm laying them, I'm seeing as much as 10mm differential in the vertical beam height. This is sometimes owing to nobbles in the concrete on the bearing face, easily knocked off with a chisel. However, some are harder to sort, needing a full re-dress with a grinder. Is this normal? Or should I be turning a blind eye to 10mm deviations in the installed surface?

[Canski]

The ones I get are usually ok on the ends apart from the odd one or two so I wouldn’t be happy with your delivery. It’s lucky you had to cut them. I would have sent them back. The 10 mm wouldn’t bother me  but then I don’t usually get involved with the insulation or screed but it allways  looks ok in the end. 

[Dave Jones]

all normal. 10mm nothing in floor makeup.

 

make sure you sit the beams on dpc, hard to tell from the pics.

[Mulberry View]

10 minutes ago, Dave Jones said:

all normal. 10mm nothing in floor makeup.

 

make sure you sit the beams on dpc, hard to tell from the pics.

 

OK. not so bad then.

 

The middle sleeper walls are 215mm blockwork and have 250mm DPC laid on them. The outer walls are 100mm blockwork and have 450mm DPC laid to allow me to turn up and over the top. More, I think, than is needed, but we love a bit of overkill at Mulberry View.

 

 

The raised up part is the Living Room, lovely to get an impression of the size now for the first time.

 

The photo was taken from the Dining portion of the Kitchen/Dining Room. I hope to have these two rooms done tomorrow, well in terms of beams laid and spaced.

 

Can anyone give me tips on grouting?

[bgmill]

We've upped our beams to 225mm deep to mitigate bounce but now I'm wondering if our 440mm centres will be sufficient. We have lots of 5m+ spans with our longest being almost 7m.

[Mr Punter]

1 hour ago, Mulberry View said:

Can anyone give me tips on grouting?

 

Give the floor a good soak with a hose.  Use a sloppy sand cement mix and brush it in.  I have used sharp sand cement before but building sand is easier.

[Mulberry View]

1 hour ago, bgmill said:

We've upped our beams to 225mm deep to mitigate bounce but now I'm wondering if our 440mm centres will be sufficient. We have lots of 5m+ spans with our longest being almost 7m.

 

We looked at all sorts of designs, alternate wide/narrow spacings, deep beams and ended up going for all narrow spacing. I felt that this was a better option than the 225mm beams for us. I almost went for the wider beams throughout, I have these for the Car Port, they're savagely heavy, I'm so grateful we didn't as they are 56kg/m and would have totally ruled out me moving them around without machinery.

 

I put these ones inside the perimeter using a 3T Digger, but have manually handled them since.

 

The shape of our building is not optimal for energy efficiency, but it does benefit from allowing for short beam spans. Our longest span is 3.9m, hoping for no noticeable bounce.

[Mulberry View]

1 hour ago, Mr Punter said:

 

Give the floor a good soak with a hose.  Use a sloppy sand cement mix and brush it in.  I have used sharp sand cement before but building sand is easier.

 

Thanks! Is it best to fill the beam gaps with cement first, then grout after?

 

Any guidance on what sort of quantity of grout will be needed? The floor is 129m2.

[BartW]

Don't forget to paint all beam ends with black bitumen paint. Essential to prevent corrosion of rebars.

 

Also, the 10mm is due to "natural" camber.

 

Quite surprised you had to cut them, as it is possible to order full design with beams in the correct size for your application.

 

 

[Mulberry View]

14 minutes ago, BartW said:

Don't forget to paint all beam ends with black bitumen paint. Essential to prevent corrosion of rebars.

 

Also, the 10mm is due to "natural" camber.

 

Quite surprised you had to cut them, as it is possible to order full design with beams in the correct size for your application.

 

 

 

I spoke with our Beam manufacturer about painting with bitumen paint and was told there is no need.

 

The discrepancy is in the comparative heights of the bearing surfaces, so isn't camber related.

 

I had to cut them due to a change in the approach of how the lower portion of our building is constructed. This meant repositioning the perimeter bearing surface and consequently having to adjust the beams to suit. Not fun, but not everything is!

[BartW]

28 minutes ago, Mulberry View said:

I spoke with our Beam manufacturer about painting with bitumen paint and was told there is no need.

 

Ok, I would check with BC if I were you. Mine point blank insisted, and wanted to see they had been done. 

 

The following source seems to suggest the same:

 

https://www.labcwarranty.co.uk/technical-blog/damp-protection-for-concrete-floor-beam-systems

 

 

[Dave Jones]

13 hours ago, Mulberry View said:

 

OK. not so bad then.

 

The middle sleeper walls are 215mm blockwork and have 250mm DPC laid on them. The outer walls are 100mm blockwork and have 450mm DPC laid to allow me to turn up and over the top. More, I think, than is needed, but we love a bit of overkill at Mulberry View.

 

 

 

Can anyone give me tips on grouting?

 

 

ref grouting, i never bother. makes no difference in my experience as it all cracks anyway when the brickies load it for the internal skin.

[crispy_wafer]

grouting - I did, as there was a slight difference in level between the infill blocks at the top of the beam, meaning that the insulation rocked a touch (of course the screed then weighs it all down and flattens the insulation out, but being green I didn't want to risk it). I mixed it up as a really runny slurry, and poured over the whole lot and used it like a filling/levelling mix.  Just make sure the blocks are wet.  Cant remember the mix, but think it was in the region of 5:1 ish...  I did my grouting after watertight, but that meant lifting the blocks to clean out all the crap that had accumulated.