JamesF's observatory build

[Swoop1]

Sawdust and shavings are evidence of progress....

[JamesF]

Indeed so, and it does feel as though I've made a fair bit of progress this week.  We're being descended on by parents and siblings plus their families tomorrow (ten adults and six children!) so I'll probably be a gibbering wreck by the time they leave, but hopefully I can get a bit more done on Sunday.

James

[Gina]

Rained all day here!!

[Peter Drew]

40 minutes ago, Gina said:

Rained all day here!!

Just like the Queen.     ?

[JamesF]

Relatives all left a little earlier than expected today, so I managed to get out to the observatory for a short while.  Had a sweep up, then made a load more mess cutting the lower section of ply for the warm room side of the internal wall and cutting a bit more insulation for the top half of the same wall.  I could have done more, but it's been a long day.

I'm hoping that tomorrow I can completely finish lining the warm room walls, finish off the insulation in the internal wall and get most of the remainder of the scope room side of the wall lined, at which point I'll be ready to start thinking about fitting the aluminium section for the lighting.  Before I do that however I might clad both sides of the door and fit the door stop.

James

[JamesF]

First job today was to finish off the insulation (just a little remaining in the internal wall), so that can now be ticked off the list of jobs to do.

After that I completed lining the warm room side of the internal wall, which means all the walls are done in the warm room now.  The roof still needs doing, but I'm not going to do that until I've made decisions about lighting for the warm room.

I also did half of the scope room side of the internal wall, leaving the section above where the lighting will start until I have the clips for the aluminium section all in place.

And then I started on the external cladding for the door.  I had to do that with the door in place because I wanted to make sure the cladding lined up with the pieces either side which meant it took a fair bit longer than it would have done otherwise and I still had the top two pieces left by the time I had to disappear off for a swimming club committee meeting.  I finished those when I got back, but it was getting dark by then so I didn't manage to get the inside of the door lined, the door stops or the lock done.  At least it means there's something for me to do in the evenings this week :)

I've not taken photos for a week so I must try to do that tomorrow.  It's changed a lot in that time.

James

[JamesF]

This evening I fitted the inside lining for the external door, cut slightly oversize and then planed down to fit neatly into the opening, at which point I realised that at least one handle might be quite useful

I could probably start a handle shop with all the spare ones I have kicking about in the workshop, but every one I found used a cupboard door type through fitting which was no use here.  Eventually I found an old door latch handle, so I've stuck that on for the time being.

I then managed to get one piece of the door stop done before dinner stopped play.  The door is now wedged shut with a length of wood, but for the first time since I started I no longer need our old back door to cover the entrance and the observatory itself can probably be said to be weathertight.

Before I started on anything however, I took some photos.

It's a tiny thing, but I'm quite pleased with the look of the door.  But for the fact that the cladding has been in the workshop whilst the rest has had a few months weathering, at first glance you don't even notice it's there.  Given another couple of months then from any distance it won't be obvious at all.

James

[Astrokev]

Looking great James. Good to hear it's now weathertight - makes a huge difference.

[JamesF]

Yes, it feels like quite a big step forward.  Even more so when I get the lock fitted, once I've found it

James

[Gina]

Coming on nicely

[Astrokev]

9 minutes ago, JamesF said:

Yes, it feels like quite a big step forward.  Even more so when I get the lock fitted, once I've found it

James

I'm always amazed and amused (and somewhat envious) by the amount of useful stuff you always seem to "just happen" to have lurking in your sheds and workshops  

[JamesF]

I do throw stuff away sometimes, honest

But having several barns and suchlike, I do also have the opportunity to plan quite some time ahead, albeit in vague terms.  Sometimes many years ahead.  Knowing that one day I wanted to build an observatory, and a brewery, and perhaps even have a "guest observatory" when we get the holiday let up and running (and the dozens of other projects I'd like to get done as well), as things have reached the end of their useful life in our house, but are still usable, or when we've had timber and suchlike left over from other work, I've put it aside rather than chucking it out.  On the one hand I admit it's a sort of hoarding (though perhaps less extreme since I generally do have a plan for the stuff I keep), but on the other it's environmentally sound

My father-in-law is far worse.  I recently had to persuade him to throw away a load of dog-eared service manuals for commercial washing machines he used to work on that no longer exist, and a couple of actual washing machine drums (he retired about twenty years ago).  I swear he still has a load of spare control units and suchlike tucked away somewhere.  They'll be in the trailer and off to the tip if I find them.

There is however going to have to be a bit of a reckoning shortly, when we need to empty the barn out so the conversion work to create the holiday let can start.

James

[Gina]

I occasionally chuck stuff out...  Only trouble is I seem to buy more than I chuck out!!

[JamesF]

Something else has sprung to mind this evening.

Whilst it was pretty miserable weather-wise this morning, around 3pm the cloud broke up a bit and it was pleasantly warm.  When I went into the observatory to take the photos at about 6pm, it was noticeably warm inside.

I have some 70mm insulation left over.  I'm wondering if it is worth popping off the ply on the southern wall and putting that in, as well as putting some in the flap before I line it.

I might also have to think about fixing some insulating to the underside of the roof.  I suspect that's where most of the problem lies, as the large sheet of black EPDM must get quite warm and presumably then feeds heat through the OSB underneath.

Or perhaps it would be better (since I have always been aware that I would need to add some ventilation) to put a vent at the top of the northern roof gable, giving warm air a way to escape.  Maybe that would be more desirable than compromising the ability of the scope room to lose heat by insulating any of it.

James

[Rusted]

An opening at the top alone will not circulate enough air. Think of a holding bottle under water. The air can't get out.

Shading southern aspects works. My open shutters block the sun from reaching the dome panels they cover.
The covered panels are at the dome's ambient air temperature. Those still exposed to the sun are at 90-95F or more.

So I've been thinking about louvres. Or even adding a complete stand-off surface with a gap for air movement.
The latter would need netting all around to stop vermin, birds and insects taking up residence.

Then there's reflective foil but it needs an air gap on its outer surface to work properly.
That air gap can be inside the closed wall. Battens can move the outer surface away from the foil.

Shade plants for a southern wall would need to be dense evergreens. Fastigiate conifers in pots?
A sack truck could move them as needed.

If stuff was meant to be thrown away you wouldn't want it in the first place.

[JamesF]

The observatory is not going to be airtight, so if warmed air is free to flow out at the top there'll always be a way for more to enter, though it would also be quite possible to add a second vent at floor level if that were insufficient.

Tomorrow and Thursday are allegedly going to be sunny, so I'll investigate further then and see how warm the internal walls get compared with the roof.  If it's mostly the roof that's the problem then I think I'll not worry about the walls too much.

James

[JamesF]

Managed to get out briefly this evening, dodging the showers (it has been an utterly miserable day here, weather-wise), and fitted all the full lengths of aluminium section for the lighting.

I found the spacing worked quite nicely with the clips if I rested them on top of the edge of the lower sheet of ply and then put the retaining screw in centered halfway between the actual centre of the mounting hole and the top of the mounting hole.  I have been supplied far more clips than I can actually use (twenty-two with each five metres of strip), so I also used some of them where there are joins, overlapping each section.  The clips aren't attached to anything else, but it seems to hold the ends together very nicely and means the join is almost invisible.  I reckon I'm going to have about 10cm left over of the 10m.

Now I just need to find a nice way to cut the mitred joins at the corners.  I think the cut-off saw might be a bit excessive for this   Could be a hacksaw and mitre box job.

James

[JamesF]

Oh, I also meant to say...

I've ordered four over-centre latches to act as permanent retainers for the roof (pics when they arrive).  They're adjustable, but I'm not absolutely convinced that they'll be quite long enough.  If that turns out to be the case then I'm bound to have a bit of M6 threaded rod lying about (who doesn't? ) so I'll just extend them a bit.  The rufty-tufty way to do it would probably be to weld an extra bit of rod on the end, but I think I'll cheat and use a rod-connecting nut, since Screwfix do them in the right size.

In the somewhat implausible event that I don't have any suitable threaded rod, I'll get Mr Angle Grinder out to play and cut the heads off some bolts.

Should I automate or motorise the roof at some point in the future then I'll probably generally leave these undone, just using them if I'm away from home or if the weather forecast doesn't look good.

James

[Yawning Angel]

15 minutes ago, JamesF said:

Now I just need to find a nice way to cut the mitred joins at the corners

I used a small aluminium mitre box, and a razor saw. The box had ridges which meant the profile was easily held by hand.

It sounds like we’ve used the clips the same way to joint the ends. Be careful fitting the plastic covers, they slide as you press them in, so you can end up with surprise gaps. They come out without damage though, so you can do ‘take 2’

I started the diffusers from the cut end of the profile, so the joints where staggered. The idea was to reinforce the profile join, in case of any movement 

[JamesF]

19 minutes ago, Yawning Angel said:

I started the diffusers from the cut end of the profile, so the joints where staggered. The idea was to reinforce the profile join, in case of any movement 

I had the same idea :)

James

[Astrokev]

22 hours ago, JamesF said:

Or perhaps it would be better (since I have always been aware that I would need to add some ventilation) to put a vent at the top of the northern roof gable, giving warm air a way to escape.  Maybe that would be more desirable than compromising the ability of the scope room to lose heat by insulating any of it.

James

I too am a little concerned about how warm the scope room will get in the sun. There's been plenty of discussion and different points of view and solutions expressed on the various threads - as with most things there's not a single solution. I've therefore opted to take a watch and wait approach. I'm expecting that I'll need to do something to deal with heat build up. I agree that it's likely most of the heating will come from the EPDM roof covering. As I mentioned in my thread, when I laid this last summer, it was too hot to stand on without shoes (I didn't want to damage the EPDM!). I've thought that I may put in vents at top and bottom, as a few folks have done. Adding fans may also be needed.

Plenty of work still to do on the observatory as the year unfolds, me thinks.

[JamesF]

I'd had thoughts about the possibility of fans becoming necessary, too.  I guess they're not a bad thing as keeping the air moving will help to prevent damp air hanging around.  There is perhaps the possibility of powering them from a solar panel too.

But we'll see what happens.  I'm not going to make any decisions until I have more information either.

James

[Guest]

Have you thought about about having opening vents at the top and bottom of the observatory (possibly automated)?  Would allow a flow of air.

Edited April 9, 2019 by Guest

[JamesF]

Yes, vents were always in my plans and probably preferable to using fans unless they turn out to be absolutely necessary.  I just haven't got around to fitting them yet.  One will go in the north gable of the roll-off roof (which isn't yet finished).  If there doesn't appear to be sufficient incoming airflow then I'll probably add an inlet down near the floor somewhere.

James

[Gina]

I have so many gaps around my scope room and ROR that vents are quite unnecessary - it doesn't get too hot on a summer day in strong sunshine even with EPDM roofing.  Even horizontal rain doesn't get in though.

Edited April 10, 2019 by Gina