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Posted: Wed Apr 15, 2009 2:06 pm
by bri
Hi I want to make my greenhouse base with these (actual photo of my base and these are 6 inches in width).
I will mortar them all level but I'm concerned about how I should distribute the weight.
Logic says I should make the arrangement such that the base of the greenhouse runs down the centre of each slab but this causes a difficulty with the internal corner ground spikes and also loses me a few inches all round of valuable floor space.
I would like to arrange everyting so that the greenhouse base internal surface runs along the inner edge of the flags so it is flush. But I am worried that this will cause the flags to sink on that edge.
My ability with these things is pretty limited as too is my experience. I'm hoping someone will have a better idea than myself as to the importance of applying the greenhouse weight. The greehouse is a 10x8 all aluminium with 4mm polycarbonate glazing.
Posted: Wed Apr 15, 2009 8:06 pm
by lutonlagerlout
lay them on 100mm of leanmix the day before
the following day sit your greenhouse on them
LLL
Posted: Wed Apr 15, 2009 8:42 pm
by GB_Groundworks
heres a photo of a greenhouse footing we did last year for a fancy greenhouse, 100mm concrete ring then a course of concrete commons for the greenhouse to sit on, and was drilled and raw plugged to the bricks.
Edited By GB_Groundworks on 1239824793
Posted: Wed Apr 15, 2009 9:34 pm
by bri
Lads I don't trust myself at all to get anything like that right that's why I'm using these flag things and getting them level is hard enough even though they are straight and flat to start with. 
I've read up , had people round, but every time I just go blank, mess it up, walk away, come back, do it again, change it, get lost, mess up, walk away etc. These little flags are my best shot. As you can see in the photo the trench I've dug for them is quite wide as I've been messing up so many times in getting things in the wrong place. Honestly I've been doing this for weeks and the time has come to 'go for it' otherwise i'll be forever putting it off.
Posted: Thu Apr 16, 2009 7:30 am
by mickg
This might seem a little complex but if you have not got a clue what to do then you need to use a template for the size of your greenhouse
get 4 pieces of 3x2 or 4x2 10' long , measure the exact internal size of the greenhouse and make a timber frame to this size and place this is the position where you want you greenhouse base to be, if the ground is too high then remove the ground until you happy that this timber frame will be in the correct position and about the right height
The first photo above is what you should have with just the internal timber frame what you will use as your guide
Knock a timber peg into one of the internal corners of your timber frame and secure your frame to this peg with a screw or nail at the height you want your base to start at
Using your tape measure measure on the external size of your frame corner to corner, write this size down and then do the same from the opposite corner to corner and write this size down, subtract one from the other and this is the amount that one of the sides need to be pushed one way or the other to make the frame square, once you have done this check the corner to corner again and both ways need to be the same length so that the timber frame is square
Knock a timber peg into the other three corners which will hold your timer frame in position, take care not to disturb your timber frame
Get you spirit level, use a level at least 3' long, don't be messing about with a little 7" boat level and starting at the corner you have fixed to the peg begin to work your way round the timber frame packing it up level using bricks or off cuts of timer
When you are happy that this timer frame is level and square fix it to the timber pegs in each of the corners, screws will be better than using nails so you don't knock it out of position
Using the top of the timber frame as you height, mix your concrete, not too wet otherwise the edging your using will sink, place your concrete in position and then put your edging on top and gently tap into position, continue until all the edgings are bedded this way and you should end up with a level and square base and the greenhouse will sit on the inside edge as you require
Posted: Thu Apr 16, 2009 9:49 pm
by bri
Wow buddy thanks for all that info. I've printed it off to read through tomorrow when out there 
Whats puzzling me though is that no one seems to consider the flags I've bought as a viable option? It seems that way but is it...are the edging flags not fit for the purpose of a greenhouse base? Just wondering as I've bought them all, they are laid down and..well..this is getting more and more expensive 
I do still appreciate all the help.
Posted: Thu Apr 16, 2009 11:25 pm
by lutonlagerlout
RTFM!
seek and ye shall find
LLL
Posted: Fri Apr 17, 2009 12:37 am
by mickg
Its not the right way to do it if your experienced, the right way is like the photos posted by GB_Groundworks, you would normally pour a concrete foundation between the 2 timber forms to hold the concrete in place until it has cured and either fix the greenhouse onto the concrete or build a wall in the centre of the concrete and fix the greenhouse on the wall, this will distribute the weight evenly, granted there is not much weight with a greenhouse but its just normal building practice to do it this way
but if you don't know how to do that and you have already purchased the concrete edgings then the only way you could achieve what you require so the foundation is flush with the inside face is to use a template as a guide
Posted: Fri Apr 17, 2009 8:47 pm
by bri
Ok tomorrow is the day I'll start on this. Doing this stuff is a bind as i lack experience and wheels...well except for my wheelbarrow that i use to go and get the sand, edgings etc.
Thanks for all your help!
Bri
Posted: Fri Apr 17, 2009 10:56 pm
by lutonlagerlout
good luck bri
LLL
Posted: Sun Apr 19, 2009 11:06 am
by bri
Ah! B*#@0%@s a mate came round to help. I tried to mortar the edges in place but found that too difficult. In the end I ended up going with my mates call which included slightly lifting some edges and squeezing a bit of mortar underneath the load bearing edge so it sat in connection with the bottom of the greenhouse frame. This was done on the premise the weight was taken on the greenhouse corner ground pegs. The mortar could have only penetrated an inch I guess. Some edges were levelled on dry mortar. But now I realise the corner pegs are not load bearing ad I'm seriously questioning the sink resistance of the base. :0
Posted: Sun Apr 19, 2009 1:14 pm
by bri
OK I have just realised something. I may not trust the secureness of the edgings as they are now but what I do have them doing is holding the base in the exact location of where it needs to be.
So I was thinking I could fit a template to the base of the greenhouse as it currently stands. Remove the base and make a full template like GB Groundworks has, and fill it with concrete.
The only thing that worries me is the wood warping from first checking it OK and perfectly straight at the woodyard to days later after rain , mist, etc. What wood do you need to get to make the template so it doesn't warp and thus the upper surface remains true to its level to be filled to? ie is there a special type of wood for this?
Posted: Sun Apr 19, 2009 2:39 pm
by lutonlagerlout
150 by 25 tanalised path edging m8
LLL
Posted: Sun Apr 19, 2009 8:54 pm
by seanandruby
If you have it in place now and it fits snug.? Knock 8 pins/stakes in as near to the corners as you can flush with the inside of the frame, then tomorrow take up the slabs and fix a string line to the outside of the pins/stakes and relay the flags level. leave 24 hours before erecting frame. As long as it sits on the flags you can always cut ( if any )a bit out of the corner, it will save you making a template. good luck sounds like you need it And don't panic, think it through first and always take a step back to look :;):
Posted: Sun Apr 19, 2009 8:56 pm
by bri
lutonlagerlout wrote:150 by 25 tanalised path edging m8
LLL
Cheers LLL. Fippin ek! Although this ain't my area of expertise I've never heard of that stuff...(the path edging bit) if I can't get path edging is there something else to fall back on. I've heard this called slatting? Is there 150x25 slatting..oh hang on its shuttering isn't it. ???
I just want to go to the wood yard and have an idea what I need.
Would you forge ahead this week...possible light frosts at night?
Yep...I ain't got a clue have I ? :p