14 hours ago, saveasteading said:

Yes , if the blocks are tight together then cement slurry will go between whereas s and c will sit on the top. For bigger gaps you need  s and c.

So I would do the cement slurry first, as it is just a watering can (without rose) and poured over the joints. It will dry out almost immediately. Then the s and c can go in the bigger gaps.

 

Doing the slurry first can lock loose or cracked blocks together and avoid damage, and is a lot easier than brushing. I seem to recall it was an official recommendation from the B and B manufacturers but maybe it was just me.

I now recall that by closing all the little gaps it stops clients fretting when looking up from a ground floor and seeing light through the floor.

 

 

Great thanks.  Blocks are tight together, but because of the profile of the beams, the gap between beam and block is a few mm at the top.  So seems like a cement slurry will get in between the blocks, and then s+c mix will fill the block/beam gaps.

 

I've got 80m2 to do, but no idea how much cement ill need!

1 hour ago, phatboy said:

 

 

 

I've got 80m2 to do, but no idea how much cement ill need!

The one I did a couple of weeks ago was 163 m but many double beams to infill I think we used 3 bags of  gravel about 2 bags of sharp sand and about 30 bags of cement so for yours I'd say 1 - 2 bags of sharp sand and 6 - 9 bags of cement. It goes a lot further if you soak the floor first. The stuff is no use stuck to the top of the blocks. 2 of you should do it in a couple of hours. I'm doing a 66m2 one tomorrow so can let you know what we use if you like.

1 hour ago, Canski said:

The one I did a couple of weeks ago was 163 m but many double beams to infill I think we used 3 bags of  gravel about 2 bags of sharp sand and about 30 bags of cement so for yours I'd say 1 - 2 bags of sharp sand and 6 - 9 bags of cement. It goes a lot further if you soak the floor first. The stuff is no use stuck to the top of the blocks. 2 of you should do it in a couple of hours. I'm doing a 66m2 one tomorrow so can let you know what we use if you like.

 

I already filled in my doubles, used a 1:3:6 mix with 10mm chippings, seemed to go well.

Yes please, let me know how you go.  And pics also would be helpful!  This self building lark sometimes throws up challenges with the simplest things!  

 

I am now regretting not grouting it before building the walls and roof..... was trying to avoid the floor pooling, but will now have a days work clearing out the joints with an old screwdriver and hoover....

5 minutes ago, phatboy said:

 

I already filled in my doubles, used a 1:3:6 mix with 10mm chippings, seemed to go well.

Yes please, let me know how you go.  And pics also would be helpful!  This self building lark sometimes throws up challenges with the simplest things!  

 

I am now regretting not grouting it before building the walls and roof..... was trying to avoid the floor pooling, but will now have a days work clearing out the joints with an old screwdriver and hoover....

I bet much of the bounce has gone since you filled your doubles ?

I'll try to get some photos if I remember

Why are you cleaning the joints out with a screwdriver and a hoover ?

29 minutes ago, Canski said:

I bet much of the bounce has gone since you filled your doubles ?

I'll try to get some photos if I remember

Why are you cleaning the joints out with a screwdriver and a hoover ?

 

There were hardly any doubles to be honest..... just at a couple of ends where there wasn't space for a block, and a quadruple for a wall to sit on.

 

I was going to clean out all of the sawdust and demolition muck that's basically filled up the joints between blocks and beams, so I could get a proper fill of slurry in there.... is this not necessary?

I'd remove the loose bits. usually a good sweep is all it needs. Or a leaf blower ? I wouldn't bother getting down with a screwdriver. They get pretty tight after grouting anyway.

Thanks @Canski , did it go well?

 

Did you first go around with the cement/water slurry in a watering can?  I can see that it looks like fairly hard work.... lots of gear to push around the place!

I'll be getting to mine over winter, now the roofs (mostly) on.

 

Thanks for the pic!

 

Tim

16 hours ago, phatboy said:

Thanks @Canski , did it go well?

 

Did you first go around with the cement/water slurry in a watering can?  I can see that it looks like fairly hard work.... lots of gear to push around the place!
 

No just mixed it very wet and brushed it in after wetting the floor. That one took 2 guys about an hour so it’s no big deal. 

pointless waste of time. screed takes care of it.

1 hour ago, Dave Jones said:

pointless waste of time. screed takes care of it.

In what way?  I have a layer of insulation between floor & screed.  Don't most people?

13 minutes ago, Roundtuit said:

In what way?  I have a layer of insulation between floor & screed.  Don't most people?

And a layer of dpm under the insulation. And a slip membrane above the insulation. 

So I finally completed this today, with no drama.

 

We did spend 2 hours pulling the sawdust and some small rubble out of the joints, as they were full in some areas.  Then vacuumed the area, and then again with a narrow nozzle over the joints.  Filled 3 vacuum bags.

 

Used a mix of sharp sand and building sand, and probably somewhere between 3:1 and 4:1 with cement, and a little plasticiser.

 

First batch was too sloppy, no consistency at all - half of it is likely on the subfloor.  The rest went a lot better, got it to the consistency of loose muffin mixture, and then with a hard brushing it all went and filled the gaps.

 

Lessons:

- When you've wet the floor on an area, wet it again (Even when the ambient temperature is about 12 degrees).

- If it seems a bit too hard to go in, spray a bit of water on the grout to go in, and brush it a bit more.

- Going over it again with the broom about 20 minutes after filling seems to clear any excess from the top surface, but it is bloody hard work!

 

All together, it took 2 of us about 90 minutes to do 60 square metres.  I did all the mixing and wetting, and my dad did most of the sweeping.  Sweeping it everywhere took longer than I had imagined.

 

Thanks for all the guidance... another job ticked off!