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Setting B&B beams on mortar??


Vijay

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Will be getting my concrete beams into place in the next week or so but I already know that because they are sitting on the ICF concrete, there is slight rocking as the concrete is obviously not totally flat. I wondered if it was an idea to lay them on some brick laying mortar to take up the unevenness in the concrete?

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1 hour ago, nod said:

There so heavy that mortar wouldn’t make any difference 

also you will need dpc under each 

or a continuous line of dpc like I did

 

I don't use a DPC unless it's on one of the load bearing internal block walls. The ICF is waterproofed concrete. I may still put a patch of DPC under each beam as you suggest though but certainly not a continuous line ;)

Edited by Vijay
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45 minutes ago, Nickfromwales said:

Once you've laid the blocks and 'grouted' they're going nowhere. Just remove any obvious snots / points of the aggregate in the concrete so the beams sit as snug as possible and away to go. 

Will do Nick. There's 100m or perimeter wall so just though some mortar might have been easier ;)

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29 minutes ago, Vijay said:

 

I don't use a DPC unless it's on one of the load bearing internal block walls. The ICF is waterproofed concrete. I may still put a patch of DPC under each beam as you suggest though but certainly not a continuous line ;)

It wouldn’t hurt

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Just now, nod said:

It wouldn’t hurt

 

28 minutes ago, Vijay said:

Will do Nick. There's 100m or perimeter wall so just though some mortar might have been easier ;)

I put a continuous line of hi load dpc right around the perimeter 

Sat the beams on then folded it over the ends and onto the block floor and laid my first course of block on it

Worked out ok for me

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23 minutes ago, Vijay said:

I'll do DPC under each beam, a spot of mortar and grout well then :)


Any tips on grouting, from what I've read soak the beams and blocks then brush in sharp sand and cement mix?

Yep all easy to do at this stage

I think we’ve all had those moments when we wished we’d just done something while we had access 

I’m having one at the moment 

Doing a bit of pointing up in the roof space 

After I’ve boarded?

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Grouting B&B - you need to make it fairly sloppy - even with wetting the beams & blocks (so there was water ponding on them) I still found it dried out quickly.  You need to be fairly forceful with the brush so that the mix does actually get down between the blocks / beams.   Its Q a fun way of spending a few hours.

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  • 2 months later...

Finally got most of the blocks in, just got all the cuts to do. I was going to grout it straight after but a builder friend said not to until I'm water tight, as the floor will pool rain water. It's something I never thought of and the reality is my house will not be watertight this year, so more than liked no roof through winter :(

 

So grout or not grout?

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Grout.  I like a mix of sharp and building sand + cement.  Any ponding will do no harm.  It is easier to do on a bigger area.  A few years ago it was not uncommon just to brush sand rather than properly grouting!  Doing the proper job with sand and cement really strengthens the floor as it ties the beams and blocks together.  If you are screeding, it doesn't matter if the finish is less than pretty.

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I found that I had to wet the blocks throughout the process - otherwise your sand/cement grout just dries up and refuse to slip down between the blocks.  You soon get the hang of it.

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Id have thought going around first with a 5:1 S/C mix to plug all the visible voids would pay dividends, followed by then mixing up a self-leveller type slurry in buckets and pouring it in? Youll never pack the gaps with mortar better than a free-flowing slurry mix will. A Lot of the ones Ive seen done have all the drips dangling down beneath them where the first lot has flowed through and cured, then a second lots been added to fill anything left. 

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It needs to start off fairly liquid - sloppy even - its got to run down between the blocks.  Wet blocks first so the mix doesnt dry out too fast, then armed with a stiff brush spread the liquid around - encourage it to pack down between the blocks.  You soon work it out.

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You MUST fill the obvious, and not so obvious voids with the S/C packing first, or the slurry will just drop through. Fill everywhere half full on the first pass and leave for 15 mins. Then go around with a bucket of the S/C mix packing where its obvious the slurry has started disappearing. Leave the first slurry to go a bit harder, prob an hour max, and then go for the final pass. 

Thats how to be sure you'll get no gaps whatsoever.

Necessary to go so nuts? Not sure, but id be doing it if it was my build. 

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It's 176m2 but I will go over it as many times as it needs to fill up the gaps :) 

 

Maybe a vibrating plate would help speed things up???

Edited by Vijay
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Just now, Vijay said:

It's 176m2 but I will go over it as many times as it needs to fill up the gaps :) 

Youll need one person mixing the slurry into a half full bucket, whilst you pour one. That'll take the ache out of backache. ;)  

A bit anyhoo :D  

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