timber frame on concrete blocks

[markyyyyyy]

When building a timber log cabin base using double up 2x6 for the permieter (where the weight of log cabin in), and resting the timber on 7n concrete blocks (x10 around perimeter) would you lay the concrete blocks on a bed of mortar, which will be on top of hardcore, or just put the concrete blocks directly on to the compacted hardcore (100mm)?

thanks

 

[noseall]

When building a timber log cabin base using double up 2x6 for the permieter (where the weight of log cabin in), and resting the timber on 7n concrete blocks (x10 around perimeter) would you lay the concrete blocks on a bed of mortar, which will be on top of hardcore, or just put the concrete blocks directly on to the compacted hardcore (100mm)?

thanks

I'd bed them on a generous sharp sand/soft sand mortar bed with a sloping fillet around the edge. Much easier to get level and stable - crucial when the shed above is being assembled.

 

[^woody^]

I wouldn't put any foundation blocks on hardcore

 

[markyyyyyy]

I'd bed them on a generous sharp sand/soft sand mortar bed with a sloping fillet around the edge. Much easier to get level and stable - crucial when the shed above is being assembled.

building merchants suggested 4:1 mix of building sand: cement

That's ok i assume?

Would i be ok to build the timber frame and log cabin right after bedding the concrete slabs in or would i have to wait 2 days for it to harden?

cheers

 

[markyyyyyy]

I wouldn't put any foundation blocks on hardcore

how would you build it?

 

[noseall]

building merchants suggested 4:1 mix of building sand: cement

standard mortar mix.

My suggestion was in view of locking the blocks in place with a slight haunching, hence bulking the mix up with concrete sand.

Would i be ok to build the timber frame and log cabin right after bedding the concrete slabs in or would i have to wait 2 days for it to harden?

​

Slabs? I thought you said blocks? Anyhoo, you'd have to wait regardless.

 

[markyyyyyy]

standard mortar mix.

My suggestion was in view of locking the blocks in place with a slight haunching, hence bulking the mix up with concrete sand.

​

Slabs? I thought you said blocks? Anyhoo, you'd have to wait regardless.

sorry, yes blocks. 4" concrete blocks - 7n.

Okay, so what ratio would you use in folllowing order - sharp sand: building sand: cement : water?

If building merchants are shut and i can't get sharp sand, i am assuming that the standard mortar mix will suffice?

 

[noseall]

Okay, so what ratio would you use in folllowing order - sharp sand: building sand: cement : water?

2 units of sharp - 2 units of soft - 1 unit of cement and enough water for a firm mix with a tiny splash of Fairy.

 

[^woody^]

I'd put the pads straight on to firm ground, not dig out and then in fill with hardcore that will potentially then settle - and settle individually and unevenly from pad to pad.

The sand cement mix is only really to level up the blocks, so should be as thin as possible.

 

[markyyyyyy]

I'd put the pads straight on to firm ground, not dig out and then in fill with hardcore that will potentially then settle - and settle individually and unevenly from pad to pad.

The sand cement mix is only really to level up the blocks, so should be as thin as possible.

interesting....

i'm ripping up decking first so i'll have to see what state the ground is like underneath

cheers

 

[noseall]

interesting....

You can get uneven settlement no matter what, in lieu of a foundation. Particularly where water and how the ground lies/slopes. As long as your base is even and well compacted it will deal with the groundwater better than fertile top soil etc.

The best solution is a foundation of course.

 

[catlad]

Consider putting some 2x2' flags down first straight on to compacted soil then put the blocks on those, gives you a bigger foot print. Find some old angle iron or similar to whack in each corner to anchor the shed to the ground.

 

[catlad]

Buy or make yourself a tamper.

 

[markyyyyyy]

my understanding is that compacting 100mm hardcore (using tamper) provides the secure solid base needed? i thought it was more solid than compact soil?

 

[noseall]

my understanding is that compacting 100mm hardcore (using tamper) provides the secure solid base needed? i thought it was more solid than compact soil?

It is. Ignore woods when he has his Sir Norman Foster/Lawrence Llewellen-bowen head on.