Reseating Greenhouse

[Mr Green]

I am reseating a greenhouse on a concrete base - about 8ft x 6ft.

I will seat it on tanilized timber lats of say half inch x one and a half inches - with rawl-bolts in the base - through the lats - and then through the green-house base.

The base is not perfectly level - once side appears to be about half an inch on the low side wrt the other three sides

I am minded to lay the wooden base lats on a mortar mix - just a skim on three sides and then half-inch on the fourth.

Any points? - use a mortar mix or some other pre-prepared mastic or similar - or even make as level as possible with mortar - let it go off - and then lay all timber on mastic?

I intend to buy the tanilized timber lats - would you treat them any more before use?

[shazzbat]

I would organise it so that the point you want the rain to run off into your water butt(s) is the lowest. Most people sit the greenhouse on its base then see where the water comes off and put the butts that end, which is a bit of a bugger if it's the inconvenient end.

Steve

[Phil L]

Why?

Why not let it go off, and then fix the greenhouse directly to it?

You are creating a problem which is unnecesary - the timber will rot - especially if it's only half an inch thick, and within a few years it will be gone, leaving gaps which the GH will slip into...simply use bolts or screws direct into the concrete if you wish to fix it down, although it can never blow away once glazed anyway.

[Dave Hill]

Where are you living? Here every winter we have winds gusting to at least 80mph, last winter

3 lots to 98mph (We can see the Mumbles light house from here and are 450ft higher than they are, and the met office record wind speed there). There is no way a glasshouse would stay put if it wasn't anchored firmly to a good heavy base. Bolt the house to the concrete, with just a damp proof membrane to keep the aluminium off the concrete, better to be safe than sorry.

David Hill Abacus Nurseries

[shazzbat]

Our site is a bit less windy than yours I think, but last week I noticed a clean strip on the blocks the GH is sat on, and it appears the recent winds have moved the GH 3 - 4 inches to leeward. I'll have to re-mount it later in the year when the weather is favourable.

Steve

[Mr Green]

I am following the instructions which say that you should put wood between the greenhouse and the base; indeed, the greenhouse sills are not flat - they need putting on a wooden support - they would not rest level straight on the base.

I did not think that tanilized timber will rot in a couple of years- that is why I was planning to use it I thought that it would last about ten years - is this incorrect?

[Dave Hill]

[Dave Hill]

I would use the larger size of tile baton that the builders merchants sell, and then keep it dry for a few days and give it a couple of coats of a good wood preserver the last coat containing a water repellent, then use a damp proof membrane between the concrete and the timber. Whilst the timber is tanalized, they are batch treated and the quality of treatment is very variable so it is best to do it yourself. I have bats' go off in less than 2 years whilst othere can last 6, 7 or even 8 yrs,

David Hill Abacus Nurseries

[Muddymike]

If you are going to all this trouble why not do the job properly and use hardwood. Go to a good timber merchant and see what they have. They may even have some oak floorboards or the like that are sub standard and can be bought for little more than tanilized pine. Still treat it before use and it will outlast you.

Some 25 years ago I knocked up a gate for a chicken run out of the best flat/thin pieces of oak from a load of slabwood sawmill waste bought as firewood. I also repaired the chicken hut with oak from the same batch, including 100% of the frame around the bottom. Only last month I visited the present owners of the cottage (it has changed hands twice, and friends of my son now own it) and was pleasantly surprised to see the same old chicken hut and run, complete with my scrapwood gate still in use. I don't know about other owners but I certainly never treated that wood in any way.

Mike