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Posted: Mon May 04, 2009 9:00 pm
by plumsource
We are having a good quality insulated log cabin / garden office 4.3 x 3m installed. Well we WERE until yesterday when the fellas came to put it up and the size of concrete base I was advised to lay is TOO *!@&ing SMALL.
We need to somehow add on 20cms to the width and length. The other nightmare is that the base is cracked so possibly not level and is definitely not square either. Measuring the 2 diagonals, there's a 20cm difference. Yes, we're bu??ered aren't we?
What;s the best way of doing this please folks? I turned down the offer of the installers building a larger timber frame on top of the existing base as it's a very heavy cabin made with thick logs and I thought it might not be stable enough.
I have a couple of new building firms coming out to look at it but wonder what you'd do in this situation?
a) break the whole thing up and start again (please don't say that - agghhhh!)
b) adding extra concrete round the edges and on top of the existing base?
or c) laying paving stones on top of the existing base to the larger dimension
At the moment we have 4 different types of plastic conduit poking up out of the corner of the concrete just to complicate things ???
Any bright ideas to get us out of the cack most welcome!!
Cheers.
Posted: Mon May 04, 2009 9:08 pm
by GB_Groundworks
so its a new slab?
and its cracked and the wrong size?
i'd get the breaker on the machine, break it up and crush it for subbase and do it right.
Posted: Mon May 04, 2009 9:11 pm
by plumsource
Aggghh! I thought you might say that. It's a month old. is that still new?
Posted: Mon May 04, 2009 9:30 pm
by DNgroundworks
Yep thats still new!
Better off doing it again and doing it right, because the 200mm of conc you will be laying around the edges will be carrying the weight of the building - not a perfect solution.
Plus its cracked and the wrong size!
Posted: Mon May 04, 2009 9:37 pm
by plumsource
Thanks guys. Appreciate it. Does everyone else agree? (my bank manager doesn't like these answers 
)
Posted: Mon May 04, 2009 9:42 pm
by GB_Groundworks
did you pour the original slab or did a contractor lay it? might be some comeback if a contractor did a bad job.
Posted: Mon May 04, 2009 9:50 pm
by dig dug dan
do i suspect it was a finnlife cabin?
They told me the wrong size too. or at least my customer brought it direct, and told me the size which she got from them.
Customer not happy. But in this instance the base was too big, and we had decked up to the base before the cabin went in. And it was a hexagonal cabin!
in the end she filled the gap with shingle.
I know this doesn't help your situation though
Posted: Mon May 04, 2009 9:52 pm
by plumsource
THE CONTRActor laid it. Hmmm yes, i think I'll have to go back to him. (disliking confrontation icon)
Thanks
Posted: Mon May 04, 2009 10:05 pm
by DNgroundworks
But was the contractor given the wrong size of base to lay from the cabin company?
Posted: Mon May 04, 2009 10:13 pm
by plumsource
digdug - no it's not finnlife but how I wish our base was too big - would be easier to resolve methinks. Esp as ours not hexagonal!
DN - erm long story, I told the contractor the measurements based on the supplier's advice to make the base exactly to the "footprint of the building". What do you guys understand by that phrase. I took it to mean external dimensions. The contractor ballsed up because it's not square (& cracked) but the installers reckoned even if it had been square, it wouldn't have been big enough for the foundation beams.
So, I'm going back to supplier to complain about duff advice and possibly the contractor for it not being square and the crack. Does that sound a reasonable plan?
Posted: Mon May 04, 2009 10:24 pm
by DNgroundworks
Yep it does,
you are correct in thinking that the 'footprint' is the external measurments well thats what i deem it to be.
The fact that it isnt square is the contractors fault, and the fact that it has cracked could be the contractors fault this due to a dpm not being laid?
It sounds like its down to the contactor, i cant see the supplier giving the wrong size of footprint and the size that they did advise to lay was not layed correctly anyway!
Hope that makes sense had a bit to much wine..............
Posted: Mon May 04, 2009 10:26 pm
by plumsource
I wish I'd had too much wine at this point - hey that's great advice thanks, I'll pour a glass!
Is a dpm a membrane? Yes he did lay one of those.
Thanks for your help.
Posted: Tue May 05, 2009 9:48 am
by Tony McC
If you need add only 200mm overall, then that's 100mm per side. I cabn;t understand why the installers cant allow this cabin to oversail by 100mm.
A simpler alternative would be to dig out around the existing base, 200mm wide to a depth of 100mm and backfill with a C20 equivalent concrete.
Then, lay heavy concrete flagstones, such as those taken up from public footpaths, on a mortar bed over the *whole* base, to achieve the correct dimensions. That should be more than capable of taking the load of a wooden cabin.
Posted: Tue May 05, 2009 5:36 pm
by dig dug dan
[quote]The fact that it isnt square is the contractors fault, and the fact that it has cracked could be the contractors fault this due to a dpm not being laid?[quote]
crack could be plastic cracking, where the concrete has drioed out too much, or, the contractor has skimped on the thickness, and made it less than 100mm
personally, i think an overasail is quite acceptable.
but the squareness of the slab is sloppy on the contractors part, and a schoolboy error
Edited By dig dug dan on 1241545347
Posted: Tue May 05, 2009 9:25 pm
by plumsource
Thanks Tony & DigDug
It can't oversail because it's built on a square foundation beam that needs to sit exactly on the edge of the base (if I've understood what you mean by oversail ie. the bearers sticking out?)
I hope I've got a solution. Adding 200mm extra concrete to 2 sides only and reinforce with rods attaching it to the main slab. New builder thinks this will be sturdy enough. I know it's not what you guys suggested but I thank you all the same for the ideas and support. The original contractor has agreed to contribute to the cost of recifying it as he's away and can't do it himself (don't want him to actually).
Cheers all x