Fixing greenhouse base?

In message , Tim Streater writes

dpends on the design. Some greenhouses come with an Al base, or can have one as an accessory that is deigned to fit directly onto concrete or whatever. Others, and typically older ones, often seem to have a bottom designed to fit on top of a wall or timbers etc. all 3 greenhouses we've had 2 in the last place, and the one here are like this.

An advantage of a course of bricks or blocks is you get some extra height in the greenhouses (at the cost of a bit more of a step into the GH.) Depending on the GH, the user and the things you might want to grow, this extra height can be useful.

It's what I used for both the GH we moved/put up in our old garden. Course of concrete block onto a concrete base, treated timbers fixed to the top with frame fixings (IIRC) and then the GH fixed to that with brass screws.

But treated timbers on the concrete would be fine I think.

chamfering sound waste of time, it's the bit at the bottom that is likely to rot first if anything as that can hold moisture underneath it.

Why not just bolt the aluminium frame to the concrete? Do you *need* to add some height?

Why don't you show us a close up of the bottom of the ali. I certainly wouldnt want to put wood there.

NT

Is the base not ally then? We got a new 6 x 8 with ally base, got a fixing kit from the manufacturer that was actually meant for another model, and just drilled through the outer flange. Inserted a plastic wallplug in each hole and then screwed into that. It seemed to us that anything else would indeed be a faff.

The only thing was that the concrete base, done by the builder while waiting for some other block/brickwork to go off, got it slightly off flat (i.e. the base was horizontal overall but not quite flat), so I shimmed it in one place to sort that. We'll wait for a nice dry day in summer before siliconing the gaps around the base and at roof level.

I did one on a dwarf brick wall many years ago. One thing that I hadn't allowed for was the thermal expansion. I had tidied it all up with a mortar fillet all round, but after a couple of seasons much of it had cracked off.

Chris

Ours was mounted on a course of bricks. An immediate advantage of this I found was it was far easier to drill through a brick when SHMBO decided that she would like a power supply in there for a propagator,heater etc and a water supply for a watering system. Same if mounted on some wood or blocks but if bolted straight down then getting services in tidely might be awkard unless you have had the foresight to leave ducts in the concrete base. Some greenhouses may have enough material under the glass that you can drill through so if yours is like that it won't matter.

G.Harman

wood was the sensible option whne I did ours in the old house. both had an inverted L shaped section at the base of the greenhouse. so it needed to fit over something. I could ahve fixed just to the brick, but that required possibly rather more accuracy in bricklaying that I could rely on - esp. as the Gh was 2nd hand in bits at the time. Fixing lengths of timber along the top first was easier to get them just the right.

The current Gh though I've just looked while ion the garden and it does have a flat base so could go straight onto a wall, concrete etc.

The profile is lipped ... it expects to sit on something

Even if I did brick a dwarf wall the top of bricks is not going to be perfectly flat enough to put the L section on, like you describe, I think it will still need a timber ...

If you put a course of bricks or breeze block down you can put a layer of render on top of them and then set the frame on to it while the render is still wet that way any small discrepancy's will be alleviated. Also you can drill straight into the block and use some frame fixings to secure it further.

Then how about some square section aluminium tube under the lip? Drill right through that, and screw to the concrete.

Or run a bead of mortar around and bed it on that (it's how my dad did his).

I did 4 rows of bricks a few years ago for ours, top row turned upside down to give a flatter surface. That was flat enough for the GH. I ran another 4 rows of bicks as an "n" viewed from the door giving a raised bed to plant into - no silly little grow bags. Oh and a hole in a brick course to bring a hose in for an automatic waterer.

Just bought 2nd hand aluminium green house - Eden 8 x 10

I am pouring a concrete base for this tomorrow ... all plants will be grown in containers/pots.

Just thinking about what/how to fit base to slab.

Previous owner has it fitted to 2x1 battens.

Thinking is that I fix 2"x2" treated wood to slab and then fit frame to that ........ as it won't be in contact with ground, hoping it will have a long life. I could chamfer edges to help water shedding.

Not sure whether I would gain anything by fitting a DPC under the timber.

Only other option would be to lay a course of bricks ... but would seem a lot of faff.

Any better ideas.

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When I had one many years ago, I mounted it on some old kerbstones that I had access to and bolted the greenhouse to them. It never moved! Then just flagged the inside and used growbags or containers.

John M

In message , timjh0 writes

There are swings and roundabouts to using beds or containers/gowbags to grow things in.

We had 2 GH in the last house, one solid floor, one with beds. Currently we have one. For a single relatively small GH I think I prefer solid floor for the flexibility it gives.

That is why I have put a slab down ... the ground will not grow anything, it would need fully raised beds ... and then you are looking to do significant changes or improvement to soil each year.

I'll use reusable grow bags ..

Wood may be easier, but rot is then to be expected, in an otherwise much longer lasting structure.

NT

In message , Tabby writes

We moved both the GH. One must have been there 15-20 years. It was was while ago now, but AFAICR their was wood under the base of one of them and that was still pretty sound

good thought .... not sure where I would get it, but maybe a uPVC window company ... some use in for strength in the box sections.