proposed wooden observatory

[m.tweedy]

I am looking to build a 6 foot diameter wooden observatory. I have plans for the dome so hopefully that part is sorted. due to a shed and high fence/trees i am looking for a wall height of around 6 feet. is there any timber type or width i should consider. any help at all would be appreciated

[ollypenrice]

I use exterior quality ply treated with the highest quality water based 'varnish,' though it is not the old style 'flake and peel off' kind. I've found that the ply thickness doesn't matter in terms of longevity so thinner is cheaper. If you use a frame construction then the ply can either be removed when clapped out and replaced, or you can panel over it again. My climatic situation will be different to yours, though. I'm at altitude in SE France so the biggest killer is UV rather than rot and sogginess. However, we do get big thunderstorms and, sometimes, heavy winter snow.

Another reason for my choice is that, in France, there is no culture of  'sheds!'  I have no idea where I might be able to find any of the traditional tanalized shiplap cladding popular in the UK. That might, in the end, be your best bet.

Olly

[nytecam]

Check my links below for my 1.8m [6ft] diam DIY dome.  Obsy raised 1m above the ground for clearance of neighbour's shrubbery !

Nytecam

[m.tweedy]

3 hours ago, nytecam said:

Check my links below for my 1.8m [6ft] diam DIY dome.  Obsy raised 1m above the ground for clearance of neighbour's shrubbery !

Nytecam

Thank you it is just what i have been looking for

[m.tweedy]

12 hours ago, ollypenrice said:

I use exterior quality ply treated with the highest quality water based 'varnish,' though it is not the old style 'flake and peel off' kind. I've found that the ply thickness doesn't matter in terms of longevity so thinner is cheaper. If you use a frame construction then the ply can either be removed when clapped out and replaced, or you can panel over it again. My climatic situation will be different to yours, though. I'm at altitude in SE France so the biggest killer is UV rather than rot and sogginess. However, we do get big thunderstorms and, sometimes, heavy winter snow.

Another reason for my choice is that, in France, there is no culture of  'sheds!'  I have no idea where I might be able to find any of the traditional tanalized shiplap cladding popular in the UK. That might, in the end, be your best bet.

Olly

Thanks Olly i am amazed at the sheer number of wood types out there.  will bear in mind what you say about the ply

[happy-kat]

Exterior quality ply is also called 'marine grade'.

[russp]

Cedar is the most often used exterior cladding these days in general building if you're looking for something that looks an bit more in keeping with a garden than ply, larch works well too and is cheaper, neither should need treatment but may last a little longer if they are.

 

[Skipper Billy]

True 'Marine' ply is very hard to find and ridiculously expensive.  Most ply sold at builders merchants sold as marine grade is actually WPB (water and boil proof) but its not really marine ply - but it is suitable for building an obsy. I wouldn't build a boat out of it though.

If you really want proper marine ply you can get it here - http://www.robbins.co.uk/marine/sheet_materials.asp

An 8x4 sheet of 15mm is well over £200 and 25mm (1 inch) is over £400 !  I WOULD build a boat out of that !  

If your builders merchant tries to tell you that their ply is marine ply ask to see the Lloyds shipping register certificate and the BS1088 type approval - thats why its guaranteed for 25 years and will probably last 40 years.

 

[happy-kat]

Phew I paid less than £20 for a sheet 7*5 , but it is working just fine outside so doing the job even is miss labeled. 

[m.tweedy]

18 minutes ago, Skipper Billy said:

True 'Marine' ply is very hard to find and ridiculously expensive.  Most ply sold at builders merchants sold as marine grade is actually WPB (water and boil proof) but its not really marine ply - but it is suitable for building an obsy. I wouldn't build a boat out of it though.

If you really want proper marine ply you can get it here - http://www.robbins.co.uk/marine/sheet_materials.asp

An 8x4 sheet of 15mm is well over £200 and 25mm (1 inch) is over £400 !  I WOULD build a boat out of that !  

If your builders merchant tries to tell you that their ply is marine ply ask to see the Lloyds shipping register certificate and the BS1088 type approval - thats why its guaranteed for 25 years and will probably last 40 years.

 

Thanks for that. I was going to try and use wooden thin planks upright like nytecam as that is what the boss wants. i really need something that looks presentable but does not cost a small fortune.

[m.tweedy]

The Observatory build has started-with a few modifications (to keep the Mrs happy). It is now an Octagon (or it will be).

Shuttering in.

Damp membrane down, concrete poured and uprights in. Tantalised and further wood preservative and bottom bit covered in

bitumised flashing.

membrane down and isolated with kingspan

THE vapour barrier and various things will hopefully happen next week.

THIS IS WHAT I AM TRYING TO ACHIEVE

*************THIS IS NOT MY OBSERVATORY*******************JUST WHAT I AM TRYING TO ACHIEVE*******************

[johnfosteruk]

Looking forward to seeing this progress, it's about the size of what we could accommodate if ever I'm lucky enough.

[m.tweedy]

For the observatory roof will i need 18mm ply or will OSB work as well?

it is going to be covered in roofing felt applied with Hot bitumen by my roofer. (another part of the agreement process with the Mrs to ensure it blends in with my shed)

[m.tweedy]

4 minutes ago, johnfosteruk said:

Looking forward to seeing this progress, it's about the size of what we could accommodate if ever I'm lucky enough.

Each side is 2 foot 6 inches (i am pre metric measurements). so just over 6 foot across

 

[cloudnine]

Looking good. I wasted a good year thinking about making a dome, and then making a roll-off-roof obsy, before deciding to buy one instead (primarily due to time-constraints and too much procrastination). Hats off to you for getting the project off the ground. Look forward to seeing how this progresses!

Martin

[m.tweedy]

 

 

 

[m.tweedy]

Finally some progress.

Not yet fixed but looking level-hopefully no shims required.

[Gina]

As has been said time and time again... Piers do NOT need to be level.  PA takes care of it.

[m.tweedy]

7 minutes ago, Gina said:

As has been said time and time again... Piers do NOT need to be level.  PA takes care of it.

I know Gina. It is for my OCD-nothing else. It just makes me feel happy when it is level.

[mwayne]

On 3/1/2016 at 15:46, Skipper Billy said:

 

If your builders merchant tries to tell you that their ply is marine ply ask to see the Lloyds shipping register certificate and the BS1088 type approval 

Do you happen to know how to tell true marine grade plywood in the US?

Thanks, Mike 

[Skipper Billy]

Well BS is 'British Standard so that wont apply in the US but the Lloyds rating is a worldwide standard so you might find that - beyond that I have no idea sorry!

 

 

[saac]

I remember looking at this when I was building my Dobsonian using the Kreige and Berry book - they would specify certain types of ply (Apple ply was one in particular) which just isn't as easy to get here in the UK. Anyway, what I did find was that the Lloyds register system is as Billy said used worldwide.  BS1088 is available from US timber suppliers   http://www.boulterplywood.com/MarinePlywood_4.htm

As an aside I've managed to get a hold of some seasoned apple wood logs - looking forward to burning them this winter, apparently they have the sweetest smell.

 

Jim

 

[m.tweedy]

builders finally turned back up today. Excuse the hat on the pier-it does not like getting its head wet.

 

[m.tweedy]

Builder has now left site. He was not able to build to the fine tolerances I wanted IE joints to be an accurate 22.5 degrees cut and join snugly.

time served carpenter now looking to finish it for me in 2 weeks time.