New Observatory Build Started!

[richyrich_one]

Before things get too heavy to move - do you have any damp proofing between the blocks and your timber base?  if not then may I suggest you get some damp proof strip and put a piece in between each timber/block.  This is the sort of stuff I mean:  http://www.wickes.co.uk/Visqueen-Polythene-Damp-Proof-Course-100mm-x-30m/p/226579?CAWELAID=120135120000016696&CAGPSPN=pla&utm_source=google&utm_medium=cpc&utm_term=&utm_campaign=Google%20Shopping%20-%20Building%20Materials&tmcampid=&tmad=c&tmplaceref=pDInpiPa&tmcustom=mkwid|spDInpiPa_dc|pcrid|43364522812|kword||match||plid|&gclid=COrDh5qsxMcCFYIcGwods7cPmQ Without it damp will move up the blocks and into your timber.

Thanks Roger.

Yes, I've used some rubber squeegee blades between the timber and blocks. I have loads of used ones kicking around and they are very durable. They are just narrower than the timber and they will spread a little as they are compressed with the weight.

Btw, your jig setup proved very useful for cutting the 21 uprights I needed as it will again when I come to the battening and cladding.

[malc-c]

Thanks Roger.

Yes, I've used some rubber squeegee blades between the timber and blocks. I have loads of used ones kicking around and they are very durable. They are just narrower than the timber and they will spread a little as they are compressed with the weight.

.

That's not the same as a propper damp corse membrane.

[richyrich_one]

That's not the same as a propper damp corse membrane.

I agree, any less effective though?

[malc-c]

I agree, any less effective though?

Personally, rubber is more permeable than polythene so I would say that there is more chance of damp migrating up into the timbers using rubber than there would be using the proper stuff.   At less than four quid for a roll it's not as if it's a costly thing to replace the rubber strips, and have peace of mind. At this stage of the build would be easy to install Rather than a year or two down the line when frames are showing signs of dampness. 

But it's your build...

[richyrich_one]

Unusually for me it wasn't a matter of saving money. I did consider using dpc, of which some are made of rubber apparently. I decided against it as I was concerned that as dpc is thin the water would collect on top of the block and get between the timber and dpc and the timber would get damp that way. If the block was narrower than the timber it wouldn't be an issue but...What I'm using gives a more substantial separation and hopefully will work.

Thanks. Always open to be educated. 

[Tinker1947]

When i clad mine i used a breathable membrane on the outside of the frame help in place with stainless steel staples, the outer cladding then when on top, on the inside a strip of 4" X 1" run along the bottom like a skirting board, with a rebate along the top on the frame side into this sheets of sterling board with another 4" x 1" along the top to keep the sterling board in place, i used 2' wide sterling board strops this allows with the removal  a  4" x 1" the whole wall open up for future repairs, additions like wiring ect, used all round the inner wall floor to ceiling....it shows in the photo further back in this thread....

[richyrich_one]

Ok, so I've been thinking about the DPC issue and have come up with this. It gives me a reasonable separation of the timber from the concrete and also won't allow the water to pool and get between the two as could happen with any size of single layer. Much happier about it now.

Thanks for the nod Roger, it's already pretty heavy.

I rolled a predetermined length of DPC around a piece of 25mm conduit which when flattened gives a 'pad' about 3mm thick and 45mm wide, just about the same width of the timber, this was important. Also as its rolled it has a slightly rounded edge to it.

[richyrich_one]

When i clad mine i used a breathable membrane on the outside of the frame help in place with stainless steel staples, the outer cladding then when on top, on the inside a strip of 4" X 1" run along the bottom like a skirting board, with a rebate along the top on the frame side into this sheets of sterling board with another 4" x 1" along the top to keep the sterling board in place, i used 2' wide sterling board strops this allows with the removal  a  4" x 1" the whole wall open up for future repairs, additions like wiring ect, used all round the inner wall floor to ceiling....it shows in the photo further back in this thread....

Sounds neat.

I'm going for a slightly different method of construction.

Frame | 18mm OSB | Membrane | Battens | Cladding

I'm not planning to board internally at this stage.

[richyrich_one]

Managed to make some more substantial progress...

These walls are seriously heavy! I thought the easiest way to construct them was to lay the frame on the obsy base and fit the osb. I did this with each wall creating a pile.

I wasn't happy leaving the pier base without any floor access so needed to cut out some liftable sections. The framework around the pier can also be lifted out should I need more serious access. Unfortunately this was after I had constructed all the walls so I had to slide them all off the base so I had access to remove the floor. Not easy on your own but necessity is the mother of invention...

With that done I just needed to slide the walls back on and tilt them up in turn and secure them.

I still had to construct the final wall with the doorway. Everything fitted together really nicely, all square and level and it's rock solid!

With the last wall up and help from my lovely wife we fitted the membrane and tarp over the whole thing. By which time it was really dark so no photo, sorry.

[richyrich_one]

[richyrich_one]

[malc-c]

Wow, your observatory will have a better warmth rating than my house...  so you'll have inner frame, presumably lined with 4mm ply or similar, then insulation, then OBS board, then vapour barrier, then an outer frame, and finally featherboard - sound and solid construction, maybe a tad over-engineered for a "shed", but it should stand up to whatever weather gets thrown at it

[nightvision]

Interesting build, great ventilation, will that be for a cavity or for the inside of the obsy?  

What is the mesh in the second to last image for (not sure but I think it will be under the floor?)?

[richyrich_one]

Wow, your observatory will have a better warmth rating than my house...  so you'll have inner frame, presumably lined with 4mm ply or similar, then insulation, then OBS board, then vapour barrier, then an outer frame, and finally featherboard - sound and solid construction, maybe a tad over-engineered for a "shed", but it should stand up to whatever weather gets thrown at it

Thanks Malcolm. I'm not planning on any insulation or any inner lining but I could always add them later. I'm going for absolutely weather proof and well ventilated. I thought over-engineered was par for the course around these parts!

[richyrich_one]

Interesting build, great ventilation, will that be for a cavity or for the inside of the obsy?  

What is the mesh in the second to last image for (not sure but I think it will be under the floor?)?

Thanks Tony, I'm hoping the ventilation will work. It's actually for both the cavity and the obsy.

By having vents positioned low down in the inner wall into the cavity and all along the roof line of each gable end I'm hoping this will provide a good quantity of air flow.

The mesh? That's to close off the bottom of the cavity to stop anything nesting in the walls!

[malc-c]

 I thought over-engineered was par for the course around these parts!

Too true, and glad to see you are upholding tradition

I'm going for absolutely weather proof and well ventilated.

Expecting any hurricans soon

[algady]

Very nice indeed.

[catman161]

Fantastic build!

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[richyrich_one]

Very nice indeed.

Fantastic build!

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Cheers

[richyrich_one]

All clad and one coat of preservative, another to do...Then I can get to finishing the roof.

[Pompey Monkey]

All clad and one coat of preservative, another to do...Then I can get to finishing the roof.

IMG_20151013_130833.jpg

Progressing nicely

I hope you get it finished before the weather turns. I know that I'm up against it with my platform/shed!

[richyrich_one]

Progressing nicely

I hope you get it finished before the weather turns. I know that I'm up against it with my platform/shed!

Thanks, me too.

Feeling up against it trying to get it weather proof before it does, which is kind of taking the fun out of it.

Hoping to get the roof structure finished this weekend and may be get the rubber fitted next week, then I can relax a bit.

[richyrich_one]

Roof structure now finished and rubber glued down. The roof must weigh a ton now but moves beautifully!

That's a weight off my mind, really needed to get that done before the weather turned.

Still need to get the two gable ends boarded and cladded, so that's my next job and then the tarp can come off for good!

[richyrich_one]

I've been busy...

Sliding door switch to get 12v to the roof for the lighting

And when you open the roof the red floor lighting comes on...

[MartinFransson]

That's awesome!! I want one! [emoji4]

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