Ray's Observatory Build

[RayD]

Well the time has come, along with the all important permission, for the start of my very own observatory build.  I've looked at lots of builds on SGL, many of which I'm really impressed with, but obviously each build has its own constraints in relation to time, money, size of garden and of course now permitted development rules.  With this all taken in to account I decided on the following as a general concept:

• Overall size to be 3.6m x 2.4m (12' x 8' in old money)
• I have decided to have a warm room, even though I do image mostly remotely, as I thought I could store equipment in there, and it could house the power supply etc.  Also it's a place to go when I've been told off for doing something wrong, as you do!  Main scope room to be 2.3m x 2.4m and warm room 1.2m x 2.4m.
• I will be using a roll off roof, custom design but really nothing new, and this is likely to be pent as I have limited space for it to open.  Being pent makes it easier to open only a section of it (I think).
• Main base frame is beam and block using 7n MD concrete blocks sat on hardcore, topped with 150 x 50 pressure treated joists.
• I am using 75 x 50 for all the general framing as I want to use 50mm Celotex insulation with a reasonable air gap.
• I will be using a steel pier on a 1m3 plug.

I think that's about the general overview, and I have drawn it all up in CAD and Sketchup for a 3D perspective (SWMBO doesn't get CAD drawings).

I know the build is going to take some time, and I'm aiming to be imaging in there by the Spring of 2017 being realistic, with total completion in the Summer.  I will try to get it done earlier but don't want to compromise quality for speed, and of course work gets in the way, with only weekends currently available for working on it.

I'll update this thread as much as I can and please feel free to throw and comments or recommendations my way as I will be explaining why I am doing what I'm doing in each post, but as it's my first observatory build I would welcome any and all comments, good or bad.

Let the build begin 

[RayD]

Delivery Day!

Ok plans have been settled, and I have decided to go with pressure treated timber.  It is a bit more expensive, but it does have a little more resilience to rot, and does also hold its shape a bit better.

Using 150 x 50 for joists and 75 x 50 elsewhere.  Also got delivery of ply for flooring and internal walls, and OSB for external walls (to be clad).

Pic 1 shows the position where the observatory is going, and as it is quite limited in space, I have to site it within 2m of the boundary, so am limited to 2.5m height.

Pic 2 is the start of the excitement to come, with the first delivery (of many).

[RayD]

Day 1

This is it, the hard bit, so on with the boots and gloves, skip at the ready, shovel and pick in hand and here we go.

Nice early start, very welcome help from my brilliant Godson, and after a general survey measure, pegging out and deciding where the high spot is, we started digging.

I decided that the plug is going to need to be quite accurate as I want it positioned exactly in the centre of the scope room, so the plan for day 1 was to level out as much as possible so that I can frame out the base to enable me to precisely mark out the plug position.  Seemed an impossible task but managed to get there, and dumped about 3 yards in the 4 yard skip.  The other yard is going in there tomorrow from the plug hole.

Holes for blocks dug down 150mm, compacted hard with heavy rammer, then filled with sub-base, rammed again and levelled off in each direction.  Blocks measured, aligned with a specific point in the garden, and squared across corners.  The rest of the blocks will be set after plug is complete.

Hard day's work that.

 

[MikeP]

Good stuff Ray.  I'll be watching with interest since I hope to start on my observatory early in the new year.

Mike

PS Whereabouts in Kent are you?  I'm on the Kent / E. Sussex border.

[RayD]

Cheers Mike, It all seems a bit daunting at the moment but once the pier base is in and the flooring down I'm sure it'll seem much easier.

I'm just outside Maidstone, so not too far from you.

[MikeP]

Quote

once the pier base is in and the flooring down I'm sure it'll seem much easier

I'm sure you are right - in many respects you will be committed at that point.  Good luck.

I'm at the "can't make my mind up stage" which on the one hand is frustrating because I want to get on with it but on the other hand, it ensures I give it plenty of thought.  I have to finish off all the jobs that SWMBO has prioritised, otherwise I might end up living in it.

Mike

[RayD]

16 minutes ago, MikeP said:

I have to finish off all the jobs that SWMBO has prioritised, otherwise I might end up living in it.

I'd actually banked on that, hence the large amount on insulation 

[SonnyE]

On 12/4/2016 at 06:25, RayD said:

I'd actually banked on that, hence the large amount on insulation 

I was thinking that maybe having a bunk in the warm room might be a good idea...

Maybe a fridge and a hotplate or microwave oven? And extra Mains Power...

Glad to see you are under way there. Great progress!

[RayD]

Thanks SonnyE. Yes the beer fridge is an essential and has already been factored in (albeit I don't drink so they are alcohol free beers). 

[SonnyE]

Proper appointments to a 'Man Cave' are essential! We must have our comforts. (I've lost track of how many times I have dosed off waiting for an image to cook. One night I woke up half frozen in the wee-hours.)

(I would want a small fridge with a freezer for microwave pizza, Jalpeno` Poppers, snacky stuff, Cheese sticks...

Golly, sounds like pretty soon I couldn't get back out the door. )

I'm toying with an idea of attaching a base to a wall right by my current spot. The place where my mount is now works very well. But I really don't have the room for an Astronomy shed per sey (except my 32 gallon dome ). But a Pier of sorts could be bolted to and slightly above a block circular wall right there and my mount attached. I think the block wall would make a great pier.

[RayD]

Ok time for an update.

Time to start digging the hole.  As noted I am keen to get the orientation pretty close as I want the pier in the centre of the scope room, but also want the framing around it to be fairly tight as I am insulating the floor.  To do this I decided to layout the main floor frame, set the corner blocks in their final position, square the frame, and then make a template for the hole out of a sacrificial piece of 9mm OSB, which not only keeps things in line, it makes it easier to control the spoil when shovelling up to transfer to the skip.  It also stops the edge of the hole collapsing in as you climb in and out.  Once dug, I will be leaving it down and using it as a base for a former to get the pour shape I want (this will become clearer later).

Today's progress then:

Final set corner blocks, all tamped down on MOT 1 sub-base, which was set firm with a rammer.  To prevent capillary action dragging water up through the blocks on to the foot plates and rotting them, I have just put a small piece of DPC on each one.

Frame square across corners and then braces screwed on temporarily using some old scraps just to keep everything in place.

Once all lined up, I measured and marked out the centres of the scope room and warm room, and lined this across to the template.  I used some old plaster corner bead I had in the garage to just hammer down in each corner just to keep the template in place.

Good old Kentish clay meant digging was really hard, so was only able to get half way down before bad light stopped play.  Happy with this though given how hard it was hand digging on my own, so should be able to finish this off tomorrow.

All my Celotex insulation was delivered today as well, so that's in the garage ready for 100mm to go in the floor once the concrete is poured and the floor framing is finished, and 50mm going in the walls and roof areas.

Also marked out all the internal joists today so can now set all the internal blocks.

Phew, earned my pizza and alcohol free beer tonight 

 

[Starlight 1]

The start never look that good but its the ground work  that counts,

[RayD]

13 minutes ago, Starlight 1 said:

The start never look that good but its the ground work  that counts,

I know what you mean.  It's certainly the hardest part 

[SonnyE]

Looks great, Ray!

You are moving right along, I like the OSB guide.

Enjoy your Pizza and Beer!

[MikeP]

Good progress Ray, you are really off and running now.

Just a couple of questions.  Please don't take them as criticism, they are intended as an honest attempt to help.

Won't you need more supports for the rim joists as well as the floor joists ie more MOT and blocks?  Will you be able to access the sides of the observatory and fence for maintenance - the base looks very close to the two fences?

Mike

[RayD]

No problem Mike, I'm more than happy for any criticism as it's the only way I can be absolutely sure I've got it right, and I can sneakily incorporate any good ideas people suggest.  I've built many things but never an observatory, so this is a first for me.

Yes I do have another 9 blocks to set on the perimeter frame and the internal joists.  I will also set some intermediate ones just on slabs and posts for extra support as it can't hurt to have too many.

17 hours ago, RayD said:

Also marked out all the internal joists today so can now set all the internal blocks.

I wanted to get the hole dug before any deep ground frosts, so set out the frame to get accurate positioning of the "jig" on just the 4 corner blocks, so now I can set all the others.

I think the camera is possibly foreshortening the view in the pics as you are right that the gaps in the pics do look small (especially for a lump like me), but the gap is actually bigger than it looks, and left for exactly the reasons you note.

Well spotted on both counts and these are exactly the types of points I'm more than happy to have as I may well (and almost certainly will) forget something along the way.

[RayD]

Just for interest, all the floor framing is held together by these little kiddies.  They are Timber-Tite joist screws, which are made for this purpose and are hardened and coated for outside use.  The Torx head also pretty much eliminates cam-out.

They're very good and really do grab, but you do need an impact driver (I use a Makita one) to get the best out of them i.e. no need for pre-drilling.

 

All the rest of the wall framing ect. will be done with my Paslode first fix nail gun using galvanised nails as I've no intentions of this ever coming down.

[Davey-T]

11 minutes ago, RayD said:

Just for interest, all the floor framing is held together by these little kiddies.  They are Timber-Tite joist screws, which are made for this purpose and are hardened and coated for outside use.  The Torx head also pretty much eliminates cam-out.

They're very good and really do grab, but you do need an impact driver (I use a Makita one) to get the best out of them i.e. no need for pre-drilling.

 

All the rest of the wall framing ect. will be done with my Paslode first fix nail gun using galvanised nails as I've no intentions of this ever coming down.

Think twice, nail once, they're a [removed word] to get out 

Dave 

[RayD]

6 minutes ago, Davey-T said:

Think twice, nail once, they're a [removed word] to get out 

Dave 

Don't I know it Dave, especially the ring ones I'm using.  I'm going to measure, measure again, go and have a cup of tea, then come back and measure once more before pulling the trigger 

[Nova2000]

Work seems to be going great Ray. I'll learn how to make a observatory by looking at this topic.! 

Cheers. Good luck

[RayD]

26 minutes ago, Nova2000 said:

Work seems to be going great Ray. I'll learn how to make a observatory by looking at this topic.! 

Cheers. Good luck

Thanks.  I'm learning as I'm going along as far as the observatory side goes, so expect to see some mistakes along the way 

[laser_jock99]

Looks like a good start, I will follow with interest.

Don't forget to creocote those timbers as they get covered over. Treated timber is okay- but treated & creocoted even better!

[RayD]

35 minutes ago, laser_jock99 said:

Looks like a good start, I will follow with interest.

Don't forget to creocote those timbers as they get covered over. Treated timber is okay- but treated & creocoted even better!

Thanks.

Yes I have to treat the sawn ends yet so may well give it all a little splash over 

[RayD]

Ok finally got the hole finished!! .  I know a cubic metre is probably OTT, but as I've just ordered my Mesu200 mount and who knows, in the future may even look at bigger OTA's, I thought whilst I'm digging I might as well keep digging.

Above noted, don't under estimate how much digging this is if you are considering doing it by hand, especially if like me you are digging in clay soil.  

Today's work consisted of getting from 500mm to 1100, then MOT type 1 again, all compacted down with the rammer.  Although not needed as this is purely a mass rather than a structural block, I had some 8mm reinforcing rods kicking about, so I put some in just to reduce the likelihood of cracking.  Not measured out or levelled, or in any specifically calculated re-bar schedule, but I had them so thought I'd use them.

Not going to do the concreting until after holidays now, so will make the former for the top at a later stage.  

I got some costs together, and it transpires that it is slightly cheaper to get a minimix delivery (1m cu being approximately 20 wheel barrows) than is to get all the stuff and hire a decent sized mixer.  All in is £192 delivered, at a mix that I can specify, and they supply 3 barrows.  About 1/2 hour for 3 of us to borrow through to the back and pour.  Much better than a day of doing it by hand.

Anyway, couple of pics below of where it's at now, and thank heavens that hole is now done!

 

 

[Davey-T]

Well we've had a few earthquakes in Kent recently Ray so can't be too careful 

Dave