50/50 Roll off build

[Yawning Angel]

After a frustrating winter with glimpses of the night sky few and far between, I’ve decided to try to join the ranks of amateur observatory owners to try and maximise my opportunities. So, inspired by @Astrokev, @JamesF and other recent builds I have permission from the missus (!) a space and SketchUp - what can possibly go wrong??

The plan is a 50/50ish roll off with warm room, weighing in at 2.4m x 4.2m and scraping in just under 2.5m high. Scope side is 2.4m square with the remainder given over to the warm side. 

The rails will extend over an area I can’t put posts in, so they’ll be supported by diagonal braces back to the main structure (this needs adding to the drawing)

The all important roof is intended to be a ‘flat’ roof design, having about a 2.5% fall from the rolling side to the warm. Waterproofing will be liquid applied - I’m lucky in this, as i work for the manufacturers, so there is some expertise to draw on - not to mention staff discount ?

Work-in-progress plan look like this:

And the plot, taken looking north (warm room to the left, scope to the right)

So I get North, East and round to South. The is already 3 core 2.5mm SWA buried, so power should be ok. CAT5 might be an issue, as all routes go under the patio. I’m hoping to get powerline networking out there, otherwise a solid WiFi setup should be manageable, as the house isn’t too far away. 

Should be a fun summer! 

[JamesF]

Good luck with your build.  Getting a rough design in Sketchup is great.  It gives you much more of a feel for how things will end up.  I look forward to seeing your progress.

Powerline ethernet seems to work well for some and not for others, but is definitely worth a try because it's relatively cheap.  If all else fails taking a network cable or two between the house and observatory on a catenary would be an alternative. You just need cable with a UV-stable sheath.

James

[JamesF]

Oh, another thing... For my design I've used (in old money) 6x2 timbers for the floor and doubled them up around the outside (so they're effectively 6x4).  My wall timbers will be 3x2, which leaves an inch of the floor timber protruding to carry the edge of the floor.  If the wall dimensions are the same thickness as your outer floor timbers then you'll need something else to support the edge of the flooring.

James

[Astrokev]

Great stuff, another build to follow ? . Good luck Alex. It's pleasing to hear that myself and James have been able to inspire you to take the plunge! One advantage of us being a little ahead of you is that you can hopefully learn from our mistakes (well mine anyway - I'm sure James won't be making many of those ?).

I concur with James' point above. My build followed similar lines in that the outer floor joists are a few centimetres wider than the wall studding which gives an edge to support the flooring. I poured over my SketchUp design for more hours than I can remember during the design stage and tried to visualise actually building the thing - where I would add bracing, attach brackets, insert screws etc etc. I found this really helped identify problems and solutions before I went anywhere near real timber.

I'll be following your build with great interest. Post loads of pics!

Kev

[JamesF]

12 minutes ago, Astrokev said:

learn from our mistakes (well mine anyway - I'm sure James won't be making many of those ?).

I wish

Mistakes are however part of a learning process, not something to be regretted.

James

[Astrokev]

12 minutes ago, JamesF said:

I wish

Mistakes are however part of a learning process, not something to be regretted.

James

Absolutely!

[tobblerone]

I’ve come to totally loving these threads! I’ve also started the process of building my own observatory but the location that I have chosen is a small hill absolutely covered in trees of a bunch of different sizes, so it will take some time just to get to the point where I can start with the foundation. But even if it may take a few years to complete atleast I have alot of time to perfect the plans and to find inspiration on this forum! ☺️ Maybe I will start my own thread later as a ”payback” as well  

Good luck with your build! Looking forward to updates!

[Yawning Angel]

On ‎23‎/‎06‎/‎2018 at 21:55, JamesF said:

Good luck with your build.  Getting a rough design in Sketchup is great.  It gives you much more of a feel for how things will end up.  I look forward to seeing your progress.

Powerline ethernet seems to work well for some and not for others, but is definitely worth a try because it's relatively cheap.  If all else fails taking a network cable or two between the house and observatory on a catenary would be an alternative. You just need cable with a UV-stable sheath.

James

Thanks James, I had thought I might run a high level cable, I can go over the patio via the existing pergola, then underground to the Obs. Clay soil and 4 weeks of no rain in making any spade work 'interesting'

On ‎23‎/‎06‎/‎2018 at 22:01, JamesF said:

Oh, another thing... For my design I've used (in old money) 6x2 timbers for the floor and doubled them up around the outside (so they're effectively 6x4).  My wall timbers will be 3x2, which leaves an inch of the floor timber protruding to carry the edge of the floor.  If the wall dimensions are the same thickness as your outer floor timbers then you'll need something else to support the edge of the flooring.

James

Very useful! I will be doubling up too, so even with the wall thickness, I should have that same edge...now I will make sure it's in the plan, to remind me

On ‎23‎/‎06‎/‎2018 at 22:22, Astrokev said:

Great stuff, another build to follow ? . Good luck Alex. It's pleasing to hear that myself and James have been able to inspire you to take the plunge! One advantage of us being a little ahead of you is that you can hopefully learn from our mistakes (well mine anyway - I'm sure James won't be making many of those ?).

I concur with James' point above. My build followed similar lines in that the outer floor joists are a few centimetres wider than the wall studding which gives an edge to support the flooring. I poured over my SketchUp design for more hours than I can remember during the design stage and tried to visualise actually building the thing - where I would add bracing, attach brackets, insert screws etc etc. I found this really helped identify problems and solutions before I went anywhere near real timber.

I'll be following your build with great interest. Post loads of pics!

Kev

I'm finding SketchUp invaluable for this job. Being able to slide the roof and see the clearances has really helped.

Next step is to get the pads in and the pier block dug out then poured 

Don't worry, there will be pictures ?

[JamesF]

1 minute ago, Yawning Angel said:

Thanks James, I had thought I might run a high level cable, I can go over the patio via the existing pergola, then underground to the Obs. Clay soil and 4 weeks of no rain in making any spade work 'interesting'

I bet   Sounds as though it would make life much easier to do it as you suggest.  Depending on how much cable you need you may find that buying it on a reel is much cheaper.  Making up the RJ45 connectors requires a special tool, but once you get the hang of getting all the wires into the plugs in the right order, which I admit can take a few practice attempts, it's not hard.  A simple RJ45 continuity tester helps, too.  (And it's always nice to be able to make up cables exactly the length you want once you know you can do it.)

The cable with the UV stable sheathing is stiffer than normal cat5e cable, but still not that bad to work with.  Apparently the standard sheathing breaks down with extended exposure to sunlight, though if it made life easier you could always run it inside some sort of conduit.  Whilst you're at it, I'd suggest running more cables than you think you'll need.  So if you think you'll only need one, run two.  Mishaps are far easier to deal with that way and if at some point you find you need extra cables then they're already in place.  A few metres of cable costs a lot less than the value I place on the time it would take to replace or add to existing cabling, so if I need one network cable I usually run two, and if I need two then I run four

Unless it's no extra cost I'd ignore anything that's cat6 rated, too.  Using cat5e will almost certainly be fine and to actually install a fully cat6-compliant cabling system is probably impractical for most people -- it's not just about buying correctly-rated components; they have to be installed to a particular specification as well.

James

[Yawning Angel]

Some minor progress today in the baking heat. Dug the pads out for the ‘shed’ base, or rather chipped out. Clay and builders rubble under turf, so it was pickaxe work. Ordered the SWA, the corner blocks and concrete and started on the pier’s foundation pit

The gazebo was the only way to make any use of the day ?

[nightvision]

Good luck with your build Alex, I've done loads of projects lately and found some local suppliers that really help keep costs down.

Check out some of the cheapest pressure treated framing timber in the country and not too far away so cheap delivery.

http://www.diyclick2buy.com/

Another local supplier (good for ply, treated framing and decking) with a great reputation:

https://www.savoytimber.com/

For shiplap/loglap these seem the best value:

http://www.ebaystores.co.uk/qualitytimberproducts  

 

Curious about the roof tech you intend to use, any more info?

 

Edited June 30, 2018 by nightvision

[Yawning Angel]

Hiya, thanks for the links I’ll devour them a little later!

The roof will be coated in a liquid applied membrane by Sika. It’s especially suited to awkward shapes, flat roofs and areas subjected to flex. This is one of the demo displays :

[Yawning Angel]

A little more progress - The concrete for the corner blocks (right-angle, internal kerbs) have arrived, so I can get those in and level. The mains SWA is ready to go, but I'm waiting on the CAT5e SWA to go in too...then, being an IT geek, I got disracted and bought a small (6u)comms cabinet and associated networky stuff for 'later' ?

Given a fair wind / fingers crossed and all that, the base should be in this weekend, sans pier. The pit should also be ready for pouring, although I really need to make my mind up if I'm going concrete all the way, or concrete / steel

[Davey-T]

On ‎30‎/‎06‎/‎2018 at 20:25, Yawning Angel said:

The roof will be coated in a liquid applied membrane by Sika. It’s especially suited to awkward shapes, flat roofs and areas subjected to flex.

We've used that on a few flat roofs, good stuff but easier when the weather is just right, not cold and not hot 

Dave

[Alan White]

Nice project and progress.
I look forward to following this.
Would love an observatory one day, but house building works stop this for now.
Good luck with your build.

Glad to see it was not only me toiling away under the sun over the weekend.

[Yawning Angel]

The foundation blocks are in, along with the network and power SWA cables - so serious grafting in 28 degree heat, especially as I've spend 20+ years perfecting my physique to drive a desk! Mad dogs and Englishmen, eh @Uplooker ?

The lawn might never forgive the brutalization in this dry weather, but that's a problem for another day. Photos later...

Next job - order the base timber

[Yawning Angel]

First major landmark I guess, the Corners are installed! The Kerb blocks worked really well, other than a bit of fun levelling one of them.  

And cable in too, I followed a field drain to use the limestone as additional protection from future over enthusiastic digging

Whilst waiting on timber for the base, it’s time to clear the remaining grass which will drop the ground level a little and get it in a skip. The area will then be covered in some weed membrane and gravelled over

[Uplooker]

11 hours ago, Yawning Angel said:

The foundation blocks are in, along with the network and power SWA cables - so serious grafting in 28 degree heat, especially as I've spend 20+ years perfecting my physique to drive a desk! Mad dogs and Englishmen, eh @Uplooker ?

The lawn might never forgive the brutalization in this dry weather, but that's a problem for another day. Photos later...

Next job - order the base timber

Ha ha, your right. I don’t stand out in the midday sun too much, being Irish.

It is actually quite funny that if you have not made an update to this thread I can just look out the window and see for myself ?

its looking good so far, onwards and upwards.

[JamesF]

Nice to see another build progressing :)  And with power already laid in, too.  I'm adopting a kind of "I know vaguely what I'm going to do about that so I'll work it out when I get that far" kind of attitude to that.

James

[Yawning Angel]

Big hole in hardened clay, building rubble and the like. 45cm a side and about the same deep - can’t imagine what it’d have been like to dig without a Newcastle shovel!

Pretty much another tick on the list, unless I get a sudden burst of energy to tackle the boulders, but I’m considering them part of the pier ??

 

[JamesF]

Get that lot concreted in and there's not much chance of it going anywhere

James

[Gina]

Looks just like my hole ?  Before I filled it with concrete.  Lots of stones and clay here too though not building rubble.

Found some old pictures of my build - been longer than I thought - 2011 - so it's 7 years old!

[Uplooker]

Looking good Alex. Unfortunately I think you managed to finish digging the hole for your pier just in time for it to fill up with water. Oh well, it will dry out ?

[Yawning Angel]

Got wood!

[michaelmorris]

Looks like a great project. I built mine about 8 years ago.

The main lesson I learned was -

A - Workout how many plug sockets you think you will need

B - double it!