Question

Evening all, I’m looking at extending my current concrete shed base outwards by 1. 2m to accommodate a larger shed shortly. My question is with regards to the shuttering for the new concrete base, will I get away for just 3 sides of shuttering as I’m extending the current pad or will I have to have a complete rectangle shutter to accomate the new cement? Hope the above makes sense?  

Answer 1

3 would be fine.  

Answer 2

I would say two pieces but put membrain down first but up to old concrete

Answer 3

Question - is original base man enough to carry new shed

Comments

@wiggly the current shed is a 8x6 and there doesn’t seem to be any issues at present and new shed is going to be around 10x6

---

Simon, then 3 sides to close in Found this - Your best bet for a good finish relies on doing three things: Making sure that the foundation for the extension is well compacted and onto good material Cut back and scable the joint with the existing 10x10 slab so that there is a good bond when the new concrete is cast. Drill and fix dowel bars into the existing slab across the joint with the extension. The number and type of bars will vary depending on the load from the new shed but you should be fine with something like 8mm (3/8") bars at 200mm (8") centres. You should probably note that this will give you a full structural connection and so may be too much for your particular problem unless you want to be absolutely sure that the slab and the extension don't separate.  

---

@wiggly that’s great cheers for that info  

Answer 4

I'd be inclined to clean the side of the cement platform and seal with some SBR so the new concrete will stick to it properly. The back wall will stop any concrete going anywhere so pin up two boards, along the front and right-hand side. Be sure to dig down a bit and lay a foundation and use some re-inforced steel grid to add strength :)

Comments

@request cheers  

---

On the side that your joining to, drill some holes and hammer some steel rods in, this will help tie it together

Answer 5

I laid this, only shuttered the front edge and butted up to the 3 sides of existing concrete. No rebar or ties on this one and one expansion joint cut in afterwards.