Setting out blockwork from foundation

[Lee Edwards]

Can’t see the need for the 100mm of concrete

Thanks for replying. I thought it was the standard way to cast a slab for a floor?

 

[robinbanks]

On the context of a garden room, I’d be unconcerned about skipping it and just putting the insulation on the dpm on the well compacted base and liquid screeding it

If you’ve already dug out for the level, crack on; it’s not a huge expense of concrete, it’s just work shovelling 3 tons of it around. Installing a liquid screed is much more a painless exercise but remember to put a membrane on top of your insulation to contain it

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Just noticed in the initial post you talked about block and beam; has that plan changed?

 

[Lee Edwards]

Hi. Thanks for your reply. It is a garden room. That is being built as a house as planning permission was required due to it having a kitchen, bathroom and mezzanine level. I was going to put in a beam and block floor but I have decided I don't want the vents.

With a beam and block floor or concrete, I still.need to figure out which blocks or bricks I need to sit a 150mm wall plate on. That's the part that is confusing me.

Cheers

 

[noseall]

Thanks for replying. I thought it was the standard way to cast a slab for a floor?

Ground bearing slab - correct.

I think there was some confusion over B&B floor v's GB slab.

 

[Lee Edwards]

Ground bearing slab - correct.

I think there was some confusion over B&B floor v's GB slab.

Hi

Yes sorry, my bad i hope I have made that cleared that up above.

 

[Russanthonypowell]

Sound like this is being over egged!!
Regarding the foundation being low in places this is a standard problem with simple solutions... for 10mm I would run the mortar bed (thick) and leave it sit there for an hour before bedding the blocks, equally if you have any access to roofslates ( unusuable 2nds are usually available of any roofing contractor cheap) just run a thin bed and lay slates with a morta bed on top for the block....dont be shy with your mortar let it squidge out and and what you strike off leave in the bottom to create a haunch around the block/ concrete/(slate).

Regarding your floor make up. 150 MOT, A sand blinding ( dont stress about 50mm its job is just to protect the membrane from MOT stones so a skittering is fine) Personally I would go 150mm MOT, Insulation direct on MOT,1200gauge membrane, 100mm concrete, ( you may need to brush up your skill set to achieve desired finish on floor, Powefloat would be my go to, but I have used one many times, although its not hard if youre practical.

Your 150mm soleplate can abridge onto the concrete floor if you do as above. Howeve if you do go for a screed and this is done afte the timberframe then dont wory about your sole plate cantilevering slightly, remember 150mm timber is usually 145mm if an off the peg CLS.

 

[Lee Edwards]

Sound like this is being over egged!!
Regarding the foundation being low in places this is a standard problem with simple solutions... for 10mm I would run the mortar bed (thick) and leave it sit there for an hour before bedding the blocks, equally if you have any access to roofslates ( unusuable 2nds are usually available of any roofing contractor cheap) just run a thin bed and lay slates with a morta bed on top for the block....dont be shy with your mortar let it squidge out and and what you strike off leave in the bottom to create a haunch around the block/ concrete/(slate).

Regarding your floor make up. 150 MOT, A sand blinding ( dont stress about 50mm its job is just to protect the membrane from MOT stones so a skittering is fine) Personally I would go 150mm MOT, Insulation direct on MOT,1200gauge membrane, 100mm concrete, ( you may need to brush up your skill set to achieve desired finish on floor, Powefloat would be my go to, but I have used one many times, although its not hard if youre practical.

Your 150mm soleplate can abridge onto the concrete floor if you do as above. Howeve if you do go for a screed and this is done afte the timberframe then dont wory about your sole plate cantilevering slightly, remember 150mm timber is usually 145mm if an off the peg CLS.

Hi

Thanks for your reply.

I am going to do the concrete and then insulation so I can do the screed last with UFH.

Good to know that the 10mm difference is ok. I was actually thinking of grinding it down a touch. I am asking around for a good brickie so hopefully someone will refer someone as they shall be much quicker than me and then I can crack on with the timber structure.

Thanks

 

[stevie888]

Why would you ever consider a beam & block floor unless there was an engineering reason?

 

[Lee Edwards]

Why would you ever consider a beam & block floor unless there was an engineering reason?

I just thought it would be easier as a diy project

 

[noseall]

I just thought it would be easier as a diy project

No.

GB slab every time.

Some site housebuilders do use B&B exclusively, regardless of ground conditions. It's probably more to do with the convenience of the void beneath and running services etc.

 

[Lee Edwards]

No.

GB slab every time.

Some site housebuilders do use B&B exclusively, regardless of ground conditions. It's probably more to do with the convenience of the void beneath and running services etc.

That's good to know. I was thinking of the ease of running drainage with beam and block floor. I will not have enough depth with a concrete slab so hoping I can just put a rest bend on the foundation as close to the wall as possible so I don't need to run it through the hardcore. Although I won't be able to concrete right the way around it.

 

[Lee Edwards]

I came across this today and I am thinking this could be what I need to do. I think in this I.age they have the concrete block on its belly with the engineering brick infront and then straddling the concrete block. So I can do this but have the block installed normally and then the bricks infront.