Topic: Heath Robinson Greenhouse - Building advice needed!

[bennettsleg]

Our inner & outer wooden hinged french doors in bedroom and lounge are being replaced this year and I don't just want to chuck them.  I'd like to turn them into a greenhouse on my plot. 

The plan is thus:
Level the area, dig holes for the frame uprights and fix in-situ. Back-fill the area with the maaaany stones available on site with a little sand ontop to fill the gaps and provide an even site.
Use pallets with the gaps filled with strips of wood and the cavity stuffed with cardboard for the base (insulation and strength).
Finish creating the frame and roof supports.
One side of the "greenhouse" will be solid (wood or more pallets) as it'll be up against the yet to be bought 6x4 shed and facing underneath a tree.
The roof I anticipate being corrugated plastic with sponge filling in the gaps around the frame and some sort of apex shaped plastic thing for the pointy top bit of the roof pitch to prevent indoor flooding...
Final internal size will be approx 4.5ft W x 9ft D x 6.2ft high at lowest point of roof.
It's going to be some serious work and forward planning is always better than messing it up!

Over to you experts.
Where am I going wrong, what pitfalls should I look out for, how did you build yours  and what should I use on the pointy bit of the roof!

[saddad]

When making shed for chickens from old doors with my dad in the 70's, there were always plenty during slum clearance, we always went for a single slope on the roof.. not quite flat but almost.. with one solid wall, the back it would be relatively easy to do, you only need an extra 3-4 inches on those dimensions to get good runoff. Avoids the problem with the gap on a pent/pitched roof (sorry can't remember the correct term). Good Luck!
 ::)

[Belinda]

Make sure you think about where and how you will fix guttering beforehand, I've seen some real bodge jobs where it wasn't thought of in advance  ::)

[Curryandchips]

Yes I would go for the single flat roof with about a 6-9 inch run off, there is a chap building one like that on our allotments at the moment and it looks brilliant. Regarding the pallets, I built my shed from recycled pallet material, but I found it far more effective to knock the pallets apart first, and rebuild as required. It is a lot more fiddly to try and fill the gaps, and with wood shrinkage, you end up with massive gaps anyway. Get yourself a 2 lb hammer and a crowbar, and those are the only tools you need. You can even salvage the nails.