Author Topic: fixing a greenhouse to its base  (Read 7792 times)


  • Not So New ...
  • *
  • Posts: 16
fixing a greenhouse to its base
« on: January 04, 2021, 21:00:34 »
Hi everyone, i was given a 8 x 6 greenhouse which is not glazed by a very nice neighbour at the allotment. I made a base of concrete footing and solid concrete blocks levelled and laid on their side on top of the footings. We moved the greenhouse onto said base, it was built up and ready to be fixed to the base and glazed. I didn't have time to fix it to the base, and in the mean time a storm has done some damage to it, but its repairable. I was going to fix treated baton to the concrete blocks and screw the greenhouse to the baton. I know the dimensions are 1928mm x 2568mm of the greenhouse, but do i need to allow any extra room to the dimensions or should the outer dimensions of the baton the same as the greenhouse (1928 x 2568) as the greenhouse will sit on it?
Does that make sense to anyone!!!!! :happy7:
Thank you for your help and advice


Tee Gee

  • Hectare
  • *****
  • Posts: 6,932
  • Huddersfield - Light humus rich soil
    • The Gardener's Almanac
Re: fixing a greenhouse to its base
« Reply #1 on: January 04, 2021, 23:20:55 »
Personally I would forget the timber and screw the base directly onto the concrete base.

What will happen over time is as water run off impregnates the timber even if the timber is treated it will eventually rot, whereas the concrete blocks won't.

If levelling up is a bit of a problem have a few washers at the ready to act as shims.

An alternative to this to to lay a thin layer of mortar on the blocks sit the greenhouse on it then screw the base down before the mortar sets.

If you go the mortar route, don't do it if Frost is forecast.


  • Hectare
  • *****
  • Posts: 17,899
  • Derby, Derbyshire (Strange, but true!)
Re: fixing a greenhouse to its base
« Reply #2 on: January 05, 2021, 07:41:12 »
Check the bottom rail, most aluminium ones have a lip that needs to overlap the base, timber or concrete, so check before you make the wooden base... if the timber is treated you should get upto a decade from it and it's more forgiving if you get the measurements slightly wrong! (Easier to alter!)


  • Hectare
  • *****
  • Posts: 7,424
Re: fixing a greenhouse to its base
« Reply #3 on: January 06, 2021, 16:03:40 »
Don't use cheap  screws they will rust out in no time. Have you thought about using imitation wood, extruded timber I think they call it. I have a garden bench made out of it, no maintenance needed at all and no rot even after about 15 years


  • Hectare
  • *****
  • Posts: 1,335
  • Plot is London clay, rich in Mesozoic fossils
Re: fixing a greenhouse to its base
« Reply #4 on: January 07, 2021, 15:39:59 »
I would:
Ensure you have sufficient headroom; its easy to build up more internal height at this stage.
Drill the aluminium to make fixings optimum, ie miss joints.
Leave all screws loose (hand tight!) until glass is in; squareness is negotiable!
Agree with shims and positioning on outer edges. Silicone seal twixt base and frame will discourage insects (ants/woodlice etc) and hold from creep.
Consider the fall to the ends where you can place butt(s)
Dont climb over glass! Use opening vent as access to ridge.
Keep a few spare sheets of glass for emergengies.
Good luck.
Freelance cultivator qualified within the University of Life.


  • Hectare
  • *****
  • Posts: 1,754
  • North London - heavy but fertile clay
Re: fixing a greenhouse to its base
« Reply #5 on: January 13, 2021, 13:24:17 »
I agree - the only bolts you should tighten before glazing are on the diagonal braces (but only after you've tested a pane in each side).

The point about headroom is excellent - the glass at the bottom of the greenhouse is almost wasted because the light it lets in mostly hits the floor.

It's a very good idea to replace the bottom row of sheets with 4mm polycarbonate (then they can't be broken by misplaced boots or disturbed pots) - but be aware that if the glass above is sitting in an S clip on the row below, then you may need to brace the clip somehow, as 4mm twinwall plastic can sag quite a bit over time (or use 10mm stuff).

Using this method could give you enough spare glass to make repairs for years - especially if you also use 4mm twinwall to shift & replace the sheets on the north side (colder, dimmer) -whenever one breaks anywhere. This has lasted me decades - including several years with a teenage football maniac the other side of one fence.

I also agree with Ace about using solid plastic to raise the headroom - I've been skip-diving many metres of L shaped Upvc cladding offcuts last year as everyone round our way is covering (not replacing) their bargeboards to save 40 years of paint and preservatives. They range from ~20-30 cm high, but they can all be bolted down and cut to the smaller size if you can't wait.

With a microholding you always get too much or bugger-all. (I'm fed up calling it an allotment garden - it just encourages the tidy-police).

The simple/complex split is more & more important: Simple fertilisers Poor, complex ones Good. Simple (old) poisons predictable, others (new) the opposite.

Deb P

  • Hectare
  • *****
  • Posts: 4,725
  • Still digging it....
Re: fixing a greenhouse to its base
« Reply #6 on: January 15, 2021, 09:37:41 »
Constructing and glazing a greenhouse is divorce threatening territory in our household........
If it's not pouring with rain, I'm either in the garden or at the lottie! Probably still there in the rain as well TBH....🥴


SimplePortal 2.3.5 © 2008-2012, SimplePortal