Odd Greenhouse Roof Construction

[wizer]

Hello

We live on a corner and as such our garden is at an odd angle. At the moment we have a cheapy 'summer house' at the end which cuts off about 6m of what was deemed as unusable space. I'd like to get rid of the summer house and make more use of the space.

So I am trying to design a greenhouse but the roof is giving me a headache. I think I'm going to use clear corrugated plastic. But I cant work out how the apex of the roof will work with the funny angle.

This make sense to anyone?

:?: :-k

 

[WellsWood]

I take it the purple bit is the plan of the proposed greenhouse?

 

[wizer]

yes sorry.

 

[WellsWood]

Does it have to have an apex? Seems like a lot of work for little reward when you get to the narrow end.

 

[wizer]

I guess not, it does have to be sloping tho with openers.

 

[9fingers]

So do you want a dual pitch roof with a ridge say parallel to the 9.8m side or depending which way is south, you might want a mono pitch to maximise the light.

The best way to solve roof type problems I find is to drawn some sections through the building solve some triangles and join up the dots.

Don't know if you are a mathematical type or not?

Bob

 

[wizer]

no, I'm generally the 'thickie' type

I have been playing about in sketchup all evening and could probably come up with something. I just wondered if there was a standard way of doing this that I am missing.

Oh and the garden points SW btw. The house is in the NE. The fences are 6ft, so I need as much clear roof space as possible to make it feasible.

 

[9fingers]

I think you need as much clear surface to catch light above the 6' fence and consider reflective surfaces below the fence line to capitalise on what light you can get in.

I'd possibly have a single pitch for simplicity.

Bob

 

[dennis]

Wizer

Do a drawing to scale of the 3.2 side giving the highest and lowest points then on this drawing measure out to scale 1m parallel on the high side and this gives you the profile to scale of the narrow end hope you understand this.

Dennis

 

[dennis]

Wizer

If you made the high point 3m and the low point on the 3.2 end 2m this would make the 10m side taper up from 2m at the 3.2 end to 2.7 at the 1m end hope this helps.

Dennis

 

[jasonB]

I would go with a mono pitched roof with the high point along the 9.8m wall.

The 10m wall would have to be higer at the narrow end to give a constant pitch to the whole roof. As said above if you draw both end elevations it is easy to work out the height difference.

Just to make it interesting you could always add a sloping side into the equasion :wink:

Jason

 

[wizer]

Thanks guys. Monopitch will be fine. What about sloping front to back? :-k

This is as far as I got this morning. Will pick it back up tonight.

 

[dennis]

Wizer

Sloping front to back is basically the same as back to front only the other way round the difference in height would be the same.You will need a purlin at the wide end running parallel at 1.6 from 9.8 side to where it strikes the 10m side.You could keep both sides level in there length and one higher than the other and put the roof on twisted with perspex sheets but with 2.2M difference between the long and short ends this would look awful you might get away with twisting a roof if there was less discrepency.

dENNIS

 

[jasonB]

I don't think it will work as drawn because the roof slope at the wide end is quite shallow, and it gradually gets steeper towards the narrow end. Thats why I said the 10m wall will have to get shorter towards the house.

Thats quite a sizable greenhouse, hope you are not thinking of growing things you shouldn't :wink:

Jason

 

[wizer]

Cheers Lads.

I think this will take a fair amount of fiddling. Thank Buddha for Sketchup.

Yes I guess it is quite large, but it's currently unused space and enclosed so shouldn't look like an eyesore. The poly tunnel on my old allotment was 10m x 5m. Tomatoes, Aubergines, Chillis and early/late spuds. Nothing illegal guv.

 

[dennis]

Wizer

On the drawing that you have done on the 3.2 end draw a line connecting the tops then using the same scale as the drawing measure out 1m from the high side and where this strikes the line that you have just drawn is the height that the lower frame needs to be at the 1m end.

As I said in an earlier post if you make the 9.8m side 3m high and level and make the 10m side 2m high at the 3.2 end it would need to slope up to 2.7 at the 1m end to give you the same slope roof.

Hope this is a little clearer as you may have noticed I,m not very good at explaining myself.

Dennis