What type of block will support concrete beam floor?

[carlosdeanos]

I have been set on a concrete slab for a while now but I am suddenly thinking of changing to a concrete block and beam. I have been specified Quinn Lite blocks for my internal leaf. They are 5.2n. This provided further insulation for my concrete slab at the sides. If I do change to beam floor, is there a specific type of block I should be using to rest the beams on? Thanks.

[Declan52]

Why would you change from a slab to a beam and block set up???

 

[nod]

I used BB because had no choice 

Far easier and much cheaper to have a slab 

No foundation blocks with BB either 

Solid concrete blocks or brick 

 

 

[carlosdeanos]

@Declan52 Hi, my soil is high clay content so I am now concerned it may sink. The slab would be way easier for me to do on my own though.

[carlosdeanos]

@nod thanks, solids it is then. I really would prefer to do slab.

[Russell griffiths]

What has your structural engineer said? 

I wanted a slab but had to go block n beam it is very diy friendly, I would say more so than slab as you do each individual job at a time, with a slab you have to get 3-4 jobs all correct before you pour that concrete, and that job is certainly not a diy job, you will need lots of help with that bit. 

 

Im upset I didn’t do a slab, but it just was so much more trouble with my site. 

however 

im glad I didn’t do a slab as I have just changed the position of a bathroom which was easy by lifting some blocks and re positioning a pipe, practically impossible with a slab. 

[nod]

1 hour ago, Russell griffiths said:

What has your structural engineer said? 

I wanted a slab but had to go block n beam it is very diy friendly, I would say more so than slab as you do each individual job at a time, with a slab you have to get 3-4 jobs all correct before you pour that concrete, and that job is certainly not a diy job, you will need lots of help with that bit. 

 

Im upset I didn’t do a slab, but it just was so much more trouble with my site. 

however 

im glad I didn’t do a slab as I have just changed the position of a bathroom which was easy by lifting some blocks and re positioning a pipe, practically impossible with a slab. 

But you will also need a crane or similar with Block and beam

and in our case 6 mtrs of concrete and a central drain periscope vents also 

and to top it a sand and cement screed 

 

[carlosdeanos]

@nod @Russell griffiths I only have an engineer to work out my steel calcs at the moment. I might just wait to see what the BC inspector says once he checks out the foundations. The extension is 8m wide and only 3.3 out, so I would only need 3m beams I think. I am just a bit confused about how they tie into the existing wall as it looks like it would be below current DPC to me, in order to get the insulation and screed on and be at the same level as the current floor.

Edited May 26, 2020 by carlosdeanos

[Declan52]

19 minutes ago, carlosdeanos said:

@nod @Russell griffiths I only have an engineer to work out my steel calcs at the moment. I might just wait to see what the BC inspector says once he checks out the foundations. The extension is 8m wide and only 3.3 out, so I would only need 3m beams I think. I am just a bit confused about how they tie into the existing wall as it looks like it would be below current DPC to me, in order to get the insulation and screed on and be at the same level as the current floor.

They don't need to tie into your existing wall. You need to work out from the finished floor you have what depth of screed and insulation you intend to use for the extension. This will then give you the top of the beam. From that you can easily work out what height they need to sit on and thus how many courses of block/brick to get to this height and your finished concrete height of the foundations.

[carlosdeanos]

@Declan52 This is what I believe I would need to do to tie into the existing wall. please excuse the terrible drawing, just threw it together. That is how I assume I would make this work. Going outwards from the existing wall.

 

[Declan52]

So you can either build another wall along your existing wall to hold the beams. More money.

Or bust out holes in the wall and have them sit on the existing wall. More time

Use a slab. Best option.

What is the floor construction of the house. Is  there any air bricks on the perimeter which would indicate a suspended floor, block and beam.

[carlosdeanos]

Its suspended timber and yes its got some air bricks. Yes I would much rather do slab, I think I may well just do that and make sure I compact the hardcore well.

[Declan52]

If the house has a suspended floor then you might have to go down that route. You won't know until you dig the founds and let the BC have a look. 

[Russell griffiths]

I think we have got a bit mixed up here, I certainly have

i thought originally you where talking about a house slab that the whole house would sit on, if it’s an extension then just talk to building control they will have a good idea of what is used locally for your ground conditions. 

[Temp]

We have a beam and block ground and first floor. Think our SE recommended 14N blocks in certain areas. It's less a problem for the ground floor because sleeper walls carry some of the load and reduce the span.