Astrokev

9 minutes ago, nightvision said:

 If you are height restricted (2.5m) you may not be able to increase your yellow beam size to 150x22.  You might see some distortion of the yellow beams over time.  You could consider using some carbon tape and resin between the yellow beams and also do a little pre-stressing while the resin sets.  It would be even better to use 4 x  100x22  with carbon laminated between each beam.  This would probably do the job: Carbon tape.  You would also need some laminating resin .

 

 

Thanks nightvision. That sounds an innovative approach. I've not heard of carbon tape so must do some research ?. I'll also relook at the dims of the beams; I may be able to increase these slightly.

15 minutes ago, JamesF said:

My slight concern about your roof design is that "stuff" can roll off it into the obsy whenever it's open or being opened or closed.  I might be tempted to put a raised lip on the end of the slope to deflect anything that has run down the roof to the sides.

I may, of course, be worrying about nothing

James

Thanks James. No, that's a fair point. Sadly, there's a biggish hedge to the West and a fairly tall Lailandii (both owned by next door neighbour) which tend to shed all kinds of rubbish. I gave this a severe trim last year and have just had another go at it, reducing the height a little bit more hoping that the neighbour won't notice, but there's only so far I can go! There's also a huge pine tree ~25m away which sheds needles by the ton at certain times of year.

I will be installing a gutter at the bottom of the slope which may help reduce the risk but I'll certainly give this some thought!

I think @yesyesused this design, so would be good to hear from him when he's next on the thread?

My thoughts are now returning to the rolling roof. Once the EPDM on the warm room is down (hopefully tomorrow), this is the next job. This post is to ask folks views on whether the design shown below will be rigid enough across the width of the obsy. Pic 1 is a general 3D view. Pic 2 is a sectioned orthographic view looking along the apex, with the side panels removed for clarity.

Key = Parts shown in green, yellow and blue are the rolling roof. Red parts are the position of the V wheels.

I've only shown a couple of green joists for clarity. In total there will be 6 or 7 (haven't decided yet).

The pale grey timber is the fixed dividing beam separating the warm and scope rooms.

The yellow and blue beams span approx. 2.3 m unsupported apart from at their ends.  For the yellow beam, my plan is to use 2 lengths of 45x95 timber screwed together, making a beam 95 (vertical) x 90 (horizontal) in size.

For the blue beams, one is 120(V) x 45(H), the other 95(V) x 45(H)

Now that I've felt the weight of the EPDM, although the load will be spread out, I'm concerned that the beams may bow in the middle over time. The separation between the grey dividing beam and the yellow roof apex beam is about 30mm, so there's not much room for movement in the beam if it does start to bow.

What do folks think?  Do I need to consider a different design to increase rigidity and reduce risk of bowing?

Thanks

The weather has improved slightly so I had to roll out the EPDM to check dims. Good news is that all is well - in fact it's a little larger than I ordered so should remove risks from my measurement errors. I've cut the piece I need for the warm room but will probably leave this until tomorrow now, when I have more time. I'll mark up the roof this afternoon and finally decide which areas I'll use contact adhesive and which WBA.

A question to those who've used EPDM - it comes with a fair amount of powder covering the surface which they say is  to make handling easier. Does this impair adhesion at all, or should I try and remove it before applying adhesive?

Thanks

5 hours ago, Kev M said:

In the process of planning a roll off roof myself and I think this is a wonderful write up.

Just thought I would say well done so far and I hope you dont mind me borrowing some of your ideas ( well most of them actually !

Thanks Kev, that's kind of you to say.

Feel free to borrow as many ideas as you want - the reality is that these are not really my ideas at all, as I pinched most of them from other builds! I think that's the whole point of this forum - to share ideas and experience so we all benefit. I have certainly been inspired by many builds over the last 5 years or so and have been cherry-picking ideas from others along the way for when I eventually (and it took some time for me to start in earnest) made a start. The main build that inspired me most was @yesyes, and I recommend you dig out his build from a few years back, but others include @RayD, @Gina and @Malc-c. All excellent builds.

I'm enjoying the project and like to share as much as I can. If others enjoy following my build as much as I've enjoyed following others, then job done ?.

Well, the replacement EPDM has just arrived.....

and now it's started to rain. The BBC weather app gives a 2% chance of rain in the next hour. Huh! My luck is doing too well at the moment ?

I've been playing around with how to fit the EPDM around the corners of the warm room roof. I believe the traditional way is to use folds similar to when making a bed. Unfortunately, this doesn't work with my design, since I want to cover both the roof and the adjacent rail beams with a single piece of rubber. Because the roof slopes, the angles of the roof and rail are different and trying to fit a single piece snugly around all the timber just doesn't work. Despite playing origami with some EPDM off-cuts, I've concluded that it's impossible to get a good fit around the OSB without cutting into the corner, which would obviously risk water getting to the OSB. I should have considered this more fully when I designed the roof.

So, here's my solution. I hope to first fit a corner piece (2nd pic) to give good protection of the roof edges ( I say hope because once the rubber is glued-up it may all go horribly wrong when trying to fit it into the c.2mm gap between the roof and the rail). Then the main EPDM sheet will be cut and folded as shown. It's difficult to illustrate this clearly in 2D but hopefully you can see what I mean in the sketchup diagrams and the feeble photo of me trying to hold the rubber with one hand. The end result gives much better protection of the OSB - I hope.

46 minutes ago, yesyes said:

Glad to got it sorted.

Did you get to keep the wrong sized sheet? I kept all my offcuts and found them quite useful for all sorts of things.

Sadly not Chris. TNT collected the wrong one a short while ago. 

There will be some left overs, and I've got a fair bit left from my pond revamp last year. I'm sure these will come in useful for sealing the nooks and crannies to keep the worst of the weather out ?

Rubber4roof update. 

The very nice man was hugely apologetic (as expected) and is to send out the corrected order today. 

I guess you can't expect more than that. 

Looking forward to cutting some rubber ?

Not much action on the observatory today then after all, but I did put up a bit more of the breather membrane around the warm room. Beginning to look quite cosy in there now and starting to get a feel for what it will be like when it's fully walled-out.

The full obsy image looks a bit of a bomb site. The EPDM on the roof is a patchwork of off-cuts from last year's project of relining the pond and is just to keep dew off the roof. Taking no chances! The bent uprights in the middle pic are camera distortions - honest!

1 minute ago, Gina said:

Ooooh!!!  That's bad!  Good job you checked before you hauled it up onto your roof!  No doubt they'll be all apologetic but a replacement will still take time to deliver.

Yeah, it's the lost time that annoys most. Even though I'm now retired and theoretically have more time (I honestly wonder how I ever found time to work before retirement), trying to align free time when the weather is decent isn't easy!

1 hour ago, Gina said:

I probably spent a couple of grand on my observatory but that's nothing compared with everything else astro and it was well worth it   I didn't add everything up - there were so many odds and ends, there must have been thousands of items and all those little things add up to an enormous amount!!

You're right there. In order of total cost to date: 1st=Timber. 2nd=EPDM. 3rd=V track and wheels. 4th=small metal brackets.  BRACKETS! Who would have thought it!

I'm obsessive-compulsive when it comes to lists n things. I've got so many spreadsheets and pivot tables related to my astro stuff and obsy it worries me sometimes. Being a retired scientist probably explains it!

Ignoring the pier, actual building costs are currently around £1700. I don't expect much change out of £2500 when it's finished. But as you say Gina - it'll be well worth it!!

Well, Saturday was wiped out due to my daughter hurting her ankle and us having to spend the morning waiting in-line at the walk-in medical centre. Fortunately she's OK and will fully recover in 4-6 weeks.

So, this morning was the big day - unwrapping the EPDM and getting it stuck on the warm-room roof.

Here's a picture of the said EPDM stretched out on the lawn to check it over. Lovely you might think - and that's what I thought until I got the tape measure out, just to check. They wouldn't send me the wrong stuff, would they? Well, it seems I was wrong, and yes, they have sent me a different size to what I ordered.

I ordered a length off of the 3.53m wide standard roll. They got the length correct, so are able to use a tape measure, but sadly they seem to have cut it off of the wrong roll, sending me the standard 3.05m wide material by mistake.

How cross am I? I'll leave you to figure that one.

To add insult to injury, in a separate order they also sent me a 9" roller when I ordered a 4" mini-roller. I forgave them that as it's only a few quid and not worth the hassle of returning it, but a >£200 EPDM order is a different thing.

So, tomorrow I'll don my Mr. Angry hat and there'll be a very irate phone call to Rubber4roofs!

1 hour ago, Gina said:

I've done the same at Wickes ?  But for my observatory I used a local timber merchant at about half the price (but still £600 worth).

I shopped around the area but, to be honest and all things considered, Wickes seemed to be the best. But you're right, the costs rack up. I'm keeping a complete list of costs for everything that goes into the observatory, but beginning to wish I hadn't started this - it's getting quite scary ?. Good job the build has taken a long time to get to this point, to spread the cost!

Looking good. 

How did you find the quality of the long joists? I had them spread out over half the floor at Wickes to find the straight ones that weren't twisted! I'm OCD when it comes to buying straight timber. I think RayD called it playing giant Jenga. They must love me at Wickes ?

Spent the morning checking out a beautiful second-hand scope. My will-power collapsed and I collect it next week. Happy bunny!

By the time I got home the day was largely gone, but found time this evening to make a bit more progress. OSB cut and screwed in place on the warm room roof. Hope to do battle with the EPDM tomorrow. Have to admit to feeling a bit nervous; never used it before and the bottom corners look a little tricky. Contact adhesive seems pretty unforgiving if I don't get it right first time. Watch this space...

2 hours ago, Dr_Ju_ju said:

Like Gina, I've used concrete to fill 2 part, air conditioning ducting 300mm & 150mm. Nothing will move it now, & I pity the next owners who want to remove it as it goes 2m into the ground.

Likewise.

My 280mm concrete filled air-con duct is bedded into a 750mm concrete cube. It ain't goin' nowhere!

4 hours ago, Adam J said:

I seem to recall starting mine at the same time as you. Must me getting close to a year now. ?

Yep, 1 year in July, though I recall you saying your's was "tiny" ?.

In my defence, the weather was pretty shocking in late summer, together with lots of other things going on in my life last year...….

Hopefully making up for it now though ? 

Found a bit of time this afternoon, so was able to nail the insulation in place to prevent it "riding up" and potentially impeding air flow through the insulation-OSB gap. Also managed to bash my thumb and index finger in the process, causing the air to turn blue for a few minutes. Fortunately the spilled blood is out of shot in the attached images. Also drilled a series of rather crude holes (difficult to hold the drill steady with my fingers wrapped in kitchen towel) through the top beam, to connect the roof space (such that it is) to the scope room, allowing some movement of air through the space. At least that's the theory.

30 minutes ago, JamesF said:

On the subject of showers and tiling, I will never go there again.  We put in a new en-suite a couple of years back and also replaced the tiles around our main bath/shower with this sort of thing:

https://www.diy.com/departments/splashwall-star-dust-single-shower-panel-l-2-42m-w-1-2m-t-11mm/161489_BQ.prd

 

Thanks James. My daughter has something similar to this stuff in her flat and I was indeed considering not replacing tiles - too many opportunities to fail! Expensive stuff though (we have big showers), but perhaps not as expensive as fixing it when it goes wrong!

So, it seems that my shower units are shot, water having gotten behind the wall tiles in both shower cubicles, which are now loose. My friendly plumber says the only solution is to rip out the cubicles and shower trays, remove all the wall tiles and probably the plaster board behind, and retile and fit new cubicles. What joy!

So, to relieve my anxiety, I decided to do some work on the observatory ?.

Time to work on the roof. Hooray. Cut and installed the foam insulation to the warm room and, in shaving the pieces down to fit between the joists, got completely covered in bits of foam due to static. It feels good to be able to stand inside the warm room now that it has a real ceiling (well, I still need to fit thin ply as an inner covering). The images show the design of the ventilation to prevent condensation affecting the inner side of the OSB. The wooden outer covering is a sheet of MDF I was using to clamber over the roof. Apart from being pleased that it took my weight, it also shows the gap between the insulation and what will be the OSB sheets, and how this air gap is ventilated by the soffit vents (just the holes at the moment. I won't fit the vents until after I've painted the obsy). I still need to drill holes through the vertical length of timber at the top of the warm room slope to allow a flow of air through the space.

Pleased to have got this done. Next job is to fit the OSB sheets and start cutting the EPDM. The contact adhesive arrived today so have all the bits. Just need to get a day clear of other stuff. My lovely baby grandson (with his lovely mum) is visiting tomorrow, so looks like Friday's the day ?

7 hours ago, Dr_Ju_ju said:

If you want something lighter than EPDM, and maybe easier to apply\fix would be PVC pond liners e.g.   https://www.pondlinersonline.co.uk/product/pvc-pond-liner/ 

They are very strong, light & watertight and are even used for lining reservoirs, and much cheaper than EPDM. My pond has one & has never sprung a leak in the last 15 years....

Julian

Thanks but if you read back on my posts you'll see that I ordered and received delivery of my EPDM several days ago.

As far as I know, PVC has relatively poor UV stability so would have a poor lifespan when exposed to daylight. My intention is to never have to re-roof my obsy!

Kev

1 hour ago, JamesF said:

You have my sympathies, Kev.  We have three totally unrelated plumbing leaks since February.  Fortunately all now sorted, but there's still a lot of repair work to do.  I keep telling myself that if I don't look up then I won't know that some of the ceiling is missing.

James  

I didn't go into details, but I'm the same. Dodgy copper to plastic join resulted in half my study ceiling coming down last year (all over my PC desk). This is now repaired but I'm still redecorating. The new leak is from a family shower above the same room - big stains and very soggy plasterboard which will need replacing I think. The third leak is from an ensuite shower above a utility room next to the study. This was put out of action just after Christmas when water started pouring out of the light switches whenever you had a shower. I'm no electrician but I don't think this is a good combination.  I'm pretty handy around the house but, frankly, I've had enough. Plumber is coming on Wednesday.

At least it takes my mind off the escalating observatory costs!

Contact adhesive for the EPDM is ordered by the way. Perhaps I can repurpose it to repair my ceiling.

22 hours ago, Astrokev said:

 Never mind; loads of other jobs I can be getting on with.

 

Beginning to regret me saying those words. This morning I awoke to find water dripping through my ceiling in the room directly below the family bathroom shower.

So, work on the observatory has had to temporarily taken a back-seat while I try and save my house. At least it will give me a chance to order and await arrival of the contact adhesive for my roof membrane!

Wow, that must have been tough. I was only sawing bits of plywood and I was shattered (I blame my hay-fever ?).

Great progress James - at this rate you'll finish your obsy before mine!