Houston we have a problem.

[jimnyboy]

We are building a small extension, 4 x 6m approx, and have  hit a problem installing the mesh for a suspended reinforced concrete floor.

 

Its is being built by yours truly using my limited knowledge.  On the architects drawings it requires a suspended reinforced concrete floor which I didnt spot thinking that the floor would just be poured onto the blinding sand base. BC has been to the site and seen the issue and has spoken to the SE who we are waiting to hear from. 

 

The foundation that I have laid and started to build on has only now got 40mm of foundation showing.

 

The reason for the suspended floor was that a survey found clay on site. When I dug the foundations I found that 90% of it is on sand with only a very small area of clay in one corner at a relatively shallow depth that we dug through to get to good ground. BCO saw the trenches prior to the pour and approved them.

 

Question is; Is there a recognised work around that we can do to keep the BCO / Structural engineer happy or are we bu**ered and need to start again ( which I really don't want to do ) ? 

[ToughButterCup]

17 minutes ago, jimnyboy said:

....

Question is; Is there a recognised work around that we can do to keep the BCO / Structural engineer happy or are we bu**ered and need to start again ( which I really don't want to do ) ? 

 

I'm sucking my teeth for you.... I don't know the answer. But an SE will do. Question is; which one?  Don't forget all SEs are not the same. SEs habitually err on the side of caution. See if you can find an SE with experience of a similar problem. I am almost sure that our SE (Tanners in Eire) will give you a well-informed answer, or will know of someone who could answer your problem properly.  +353 (0)25 51000

 

Good luck! This is one question that needs a properly expert answer.  (And we aren't experts .. )

 

 

[Mr Punter]

Can you have a rethink and do a beam and block floor?  Much simpler than suspended RC.  You need at least 150 air gap under, 225 preferred.  Insulation on top, then screed or chipboard.

[jimnyboy]

OK some good news for once. Seems that the SE has given the go ahead for us to run a second trench 200 mm wide running up against the existing foundation that will then give us the with that we need to do the suspended floor ( Wish I had thought of the Beam and block option at an earlier stage ) He also wants us to place 16mm rebar every 450mm drilled into the existing foundation. So the question is, what type of adhesive do I  use to hold the rebar in place in the holes drilled into the existing foundation ? 

[George]

1 hour ago, jimnyboy said:

OK some good news for once. Seems that the SE has given the go ahead for us to run a second trench 200 mm wide running up against the existing foundation that will then give us the with that we need to do the suspended floor ( Wish I had thought of the Beam and block option at an earlier stage ) He also wants us to place 16mm rebar every 450mm drilled into the existing foundation. So the question is, what type of adhesive do I  use to hold the rebar in place in the holes drilled into the existing foundation ? 

Resin anchors, either hilti or rawlplug. The datasheets are on their websites

[Conor]

1 hour ago, jimnyboy said:

OK some good news for once. Seems that the SE has given the go ahead for us to run a second trench 200 mm wide running up against the existing foundation that will then give us the with that we need to do the suspended floor ( Wish I had thought of the Beam and block option at an earlier stage ) He also wants us to place 16mm rebar every 450mm drilled into the existing foundation. So the question is, what type of adhesive do I  use to hold the rebar in place in the holes drilled into the existing foundation ? 

You could in reality get away with just hammering the rebar in to 16mm holes, I've done this several times and with a 200mm deep hole, those bars aren't going anywhere, esp as they are to stop differential movement, not pulling restraint. Check with your SE.. tho they will almost certainly say hilti resin.