Astrokev

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

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.

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 ?

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

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.

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!

Despite being incapacitated with hay-fever today, I managed to complete the soffit and ventilation. Next job is to cut and insert the foam insulation into the roof and cut the OSB. Now I realise I need contact adhesive in addition to the WBA to stick down the EPDM, playing with the EPDM looks like it'll have to wait a few more days. Never mind; loads of other jobs I can be getting on with.

Thanks Gina, appreciate your advice. Looks like I need to revisit my friends at Rubber4roofs! Kev

Thanks Chris

OK, I've been checking out installation of the EPDM from Rubber4roofs and am now wondering whether I've got the correct adhesive ?. I bought the water based adhesive as recommended on the website, but I'm wondering whether this will be good enough for the edges, and especially for the corners, where I'll need to fold the rubber to form a neat finish (well, as neat as I can). To anyone who's used EPDM, should I also get some contact adhesive for the corners, or will the WBA stuff be adequate? Thanks

Yes, I'd considered something similar. I'm sure the seal between the rolling and fixed roof will not be parallel, no matter how hard I try, so I've been thinking how I could create a "soft/flexible" join as the roofs come together to improve the seal. A strip of EPDM as you suggest could work well I think.

Not as much progress today as I'd hoped (that seems to be a recurring theme). Bought the OSB and a 2.4 x 1.2m piece of 50mm foam insulation for the warm room roof, together with yet more studding and brackets. It seems to go on forever. In the little time left in the day, I added a double joist to support the edges of the 2 pieces of OSB I'll need to use for the warm room roof, and then moved the existing joists to make them more equally spaced. Also added studding across the back of the roof to attach the OSB to. The SketchUp drawing shows the next stage - to add a piece of ply across the back of the roof as an overhang. The holes are for soffit vents (thanks @RayD for this suggestion) which will help ventilate the small space between the insulation and the OSB. I plan to drill largish holes in the vertical timber at the "top" of the roof, that separates the warm and scope rooms, to allow a small flow of air through the roof-space to reduce risk of condensation build-up. Then, finally, I can start to play with the OSB and the EPDM ?.

Great progress James. That corner pad is a beast. There's room for a basement under there!

Thanks Chris. I've just been looking at the pics of your build (cunningly saved to my PC as a reference, since my design is based largely on yours!) and couldn't see any showing the south wall seal - in fact hardly any builders seem to show clearly how they approached this obvious challenge! Your post above now reveals all ?! Thanks for posting. Your solution looks good. My design currently has an overhang, but that's mainly because I hadn't given it too much thought. I was intending revisiting this to try and come up with a different approach but, having seen your post, maybe I should just leave it as it is!

You've probably already seen it, but Sara (swag72) has just built a steel frame rolling roof. May be worth checking that out in her thread?

I'm going with 11mm OSB which hopefully will do it? Just designing the joist positions now for the rolling roof. I will have to add a few extra to the fixed roof, which is already finished. Stupid me should've considered the size of the roofing sheets BEFORE I put up the joists! Not a major problem as more is good! Won't make that mistake with the rolling roof though.

Thanks Jas. Yes, I've considered using them somewhere in the design; just need to figure out how to make best use of them.

Not much going on on the observatory today due to other commitments. But - the EPDM rubber roofing arrived ?. Crikey, it's heavy! ? Just hoping my roof design is strong enough to take the weight. My son has promised me a trip to Wickes tomorrow in his big van to get the OSB3 sheets so, weather permitting, I hope to see some roof-action this weekend.

Hi Alex Thanks for your kind comments. A good question regarding sealing the south wall. I'm still working on my roof design and to be honest haven't yet found a method that I feel happy with, so this is a work in progress. The roof won't form a perfect seal all round of course. The E/W edges will have a small gap above the wheel track. This will be partially covered by the edges of the roof which will extend below the top of the walls and then "hook under" the top rail. This will help keep out wind and rain but won't prevent creepy crawlies entering. The northern edge of the roof will form a seal between the rolling roof and the top-most piece of the fixed roof. So, back to the southern edge. At the moment I'm thinking of using a spare strip of EPDM to form a flap which will keep out rain and wind, but it isn't the most aesthetically pleasing solution. Other builders have used this method, and I guess it works OK from a functional perspective. I'll keep thinking on this and will post my final design in the coming days, once I've finalised it, but I'm not expecting miracles. As far as I've seen in other builds, no one using a similar obsy design has yet found a perfect answer for this and I don't consider myself any better than other builders! One other consideration - I've designed the roof with a fairly generous overhang of the EPDM covered boarding, so rain ingress will hopefully not be a high risk. SketchUp is great for playing with different design solutions, but for this I may have to design on the fly once the main roof is up and can play with it for real. ?

Thanks Shibby for the nice comments. Final test will be when it's finished, and I can roll the roof off without causing havoc, and that it's fully waterproof! Thanks for the tips regarding power. I'm very much a novice when it comes to electrics, so will have to do some research regarding consumer units and circuit loading. Don't want to burn the observatory down as soon as it's operational ?. The route from the house to the obsy is not straight forward if I had to bury the cable (a 100 year old fragile mains drain runs right across the route!) so would have to be really careful if I need to bury it. Keeping it above ground would be simpler, but is not without it's obstacles either, but I can probably find a way. Then I'll need to drill through the house wall to feed the cable to access a socket. All good fun ahead!

Dave - I'd also recommend checking out the SketchUp website. There's lots of videos covering all the basics, which I found invaluable. Kev

I doubt that! Layers are really easy. As you mentioned earlier, there's loads of video tutorials on the SketchUp site.