Timber frame base footprint bigger than summerhouse

[SolRobinson]

Hi all, so after spending a week or so constructing a timber base, ready for the delivery of a prefab summer house, the summer house has turned up a different size than was advertised and the company have given me the “our terms state you should wait for the plans to arrive before constructing a base” so have left me in a bit of a pickle.

The base is now 10cm larger on all 4 sides of the garden room. The front of the garden room, has a veranda in which an 18mm decking is to be laid on. I’m thinking I can get away with laying the decking around this 10cm edge also, however a neighbour who is an ex-joiner has expressed concerns of water getting under the floor on the inside of the building.

I’m hoping that with this slim gab between the wall & base, that the wall will drop down between this gap, rather than seeping under and in. I also plan on paint/staining the cabin with Protek wood stain, which is water repellent, so should hopefully stop water from soaking through. I’ve though about putting a turned up DPC on the inside & outside, but not sure if this would make things worse.

Any advice on what should be done here would be greatly appreciated!

https://imgur.com/a/K4YpGaC

 

[freddiemercurystwin]

Build a deck on top of your base and then additional bearers on top of that but with the right footprint? Or are you maxed out on height for permitted development already?

 

[SolRobinson]

Build a deck on top of your base and then additional bearers on top of that but with the right footprint? Or are you maxed out on height for permitted development already?

Already max height, also started building the cabin, thinking I’d sort the issue out later and now this thing isn’t coming apart.

I’m thinking I could get away with some tilted timbers around the edges and then some flashing tape over that, will cause any water to run away from the cabin and the flashing should stop it getting to the base/floor

 

[Why Not Indeed]

As a person sat here on the internet who isn't the one having to do all the work, let me say....do it properly, or you'll be kicking yourself for years to come [possibly every time you look at it].
If it was me faced with the work, I'd be looking in to every bodge going!

 

[mrrusty]

I can see the problem. The dimensions were advertised as the extreme dimensions but because of the interlocks where the walls cross, the actual walls are inset from the ends of the wall beams.

I would go with sloping fillets. It's a bodge but the alternative is to disassemble and change the base.

I wouldn't use flashing tape it looks carp.

 

[SolRobinson]

I can see the problem. The dimensions were advertised as the extreme dimensions but because of the interlocks where the walls cross, the actual walls are inset from the ends of the wall beams.

I would go with sloping fillets. It's a bodge but the alternative is to disassemble and change the base.

I wouldn't use flashing tape it looks carp.

Any other suggestions to flashing tape? Only 1 section that is ever going to be visible is about 1.5m at the front… and you can paint it, so could match the decking/cabin colour… I thought it might pass?

 

[johnny2007]

Dismantle and rebuild.
Sometimes things go wrong and bodging is the worse thing you can do.
It will only take a day max, so...

 

[robinbanks]

Half a metre run of decking all the way round, make a feature of it

 

[foxhole]

Uvpc soffit and facia board all round, water proof .?