Astrokev's ROR - The Build

[Guest]

3 minutes ago, Bizibilder said:

If there is a little air circulating underneath then OSB will last for years.

We had some 18mm standard OSB round a site we developed as a screen wall. 200plus sheets. They were out in all weather for over 4 years and we ended up taken loads home each when the site completed. I put some in a make shift shed my brother now has....It's over 20yrs old now and he had the ordacity to complain the floor was starting to rot hahaha good stuff OSB and if used with thought almost indistructable. 

Almost ?

[JamesF]

I can't see the need for marine-grade ply either.  Like RayD, I just went for the hardwood-faced stuff.

James

[Astrokev]

4 hours ago, LeeRich said:

We had some 18mm standard OSB round a site we developed as a screen wall. 200plus sheets. They were out in all weather for over 4 years and we ended up taken loads home each when the site completed. I put some in a make shift shed my brother now has....It's over 20yrs old now and he had the ordacity to complain the floor was starting to rot hahaha good stuff OSB and if used with thought almost indistructable. 

Almost ?

Then again, many years ago I made a roll-off box out of OSB for the EQ mount I had at the time. Treated the outside with fence paint. Within a couple of years it was mush ?. It was only intended to be a short-term structure, which was just as well!

Edited November 20, 2018 by Astrokev

[Astrokev]

It seems that votes are split - you pays your money and takes your choice. The problem with this type of question is most individuals only tend to have experience of a single material, rather than comparative experience, so the relative pros and cons are generally biased. Nature of the beast I guess ?

I'll price up a few options and see if that sways my decision. What I think I have confirmed though, is that marine ply is probably not worth pursuing, having minimal benefit for a huge cost ?.

Thanks to all for the feedback - very helpful.

Edited November 20, 2018 by Astrokev

[Gina]

I used 11mm OSB on my warm room roof and AFAIK it's fine.  It's underneath EPDM and has polystyrene foam and 6mm plywood underneath so can't say I've actually seen it since I built my observatory seven years ago but the roof still looks flat and doesn't let any wet in so I presume it's fine.  I doubt it even gets damp.

[RayD]

18 minutes ago, Astrokev said:

It seems that votes are split - you pays your money and takes your choice. The problem with this type of question is most individuals only tend to have experience of a single material, rather than comparative experience, so the relative pros and cons are generally biased. Nature of the beast I guess ?

I'll price up a few options and see if that sways my decision. What I think I have confirmed though, is that marine ply is probably not worth pursuing, having minimal benefit for a huge cost ?.

Thanks to all for the feedback - very helpful.

Exactly that, Kev.  OSB is very strong, in fact, in sheer it is actually stronger than ply.  OSB also resists water ingress better........However, (always one of those) this means it does not dry as quickly as ply, and is why it can be prone to bad swelling, particularly at edges (even more so if cut and not carefully treated).

Both products will work just fine, the OSB will just take a little more care to make sure it stays as it was laid i.e. sealing edges and nail/screw holes etc.

[JamesF]

Well, since I recommended 18mm ply

I have a shed in which I keep some of my bee-keeping stuff, but it's a pre-fab one that you just fix the walls, roof and floor together for.  It has an 11mm OSB floor.  The shed is suspended about 8" off the ground on concrete blocks.

The OSB seems to have survived reasonably well in that it hasn't been destroyed by damp or anything like that, but it has definitely bowed downwards between the supporting timbers where I walk on it.  I had no qualms about standing on my warm room roof at the weekend which is of similar construction, but I think it's the regular travel across it that has caused the problem.  It's just not really thick enough to take the load properly.

I believe 18mm OSB or ply should be fine if there's space for air to ventilate the underside (which I know you have).  I'd guess the ply will be in the region of £10 to £15 per 8'x4' sheet more expensive than the OSB, but at the moment I can't find the invoice for my ply so I'm not sure.

I chose ply because it gives a flat surface, because it can be cut to a nice clean edge and because I know it will not be a problem if there's no support close to the places where I'm going to need to cut holes out.

James

[Astrokev]

43 minutes ago, JamesF said:

 

I believe 18mm OSB or ply should be fine if there's space for air to ventilate the underside (which I know you have).  I'd guess the ply will be in the region of £10 to £15 per 8'x4' sheet more expensive than the OSB, but at the moment I can't find the invoice for my ply so I'm not sure.

I chose ply because it gives a flat surface, because it can be cut to a nice clean edge and because I know it will not be a problem if there's no support close to the places where I'm going to need to cut holes out.

James

I've looked at the Caberdeck stuff. Looks good but it says on the tech info it should be stored and kept dry, even though it's water resistant, and is intended for internal use. Think I'm swerving away from that idea in favour of more trad materials. I think 18mm ply is currently my preferred choice, having digested the helpful views and feedback. I much prefer to work ply cf. OSB, for the reasons you state. I only need three 8'x4' sheets, or 1220x2440 in modern money. Wickes 18mm hardwood ply comes in at ~£35 a sheet. I may shop around.

Other pro's and con's of 18mm ply -

Con's - I'll have to cut it with my jigsaw, and break my handsaw-only rule in-force for the rest of the build. Plus it weighs a ton.

Pro's - It'll be able to withstand the first-light dance-party far better than 12mm, and won't splinter when I accidentally drop my EQ6 counterweights ?.

[Swoop1]

14 hours ago, Astrokev said:

Pro's - It'll be able to withstand the first-light dance-party far better than 12mm, and won't splinter when I accidentally drop my EQ6 counterweights ?.

Is'nt that what the rubber tiles will be for? Mind you, getting poleaxed by a rebounding counterwight might be a bit hard to explain at A&E......

[Astrokev]

On grandson duty today, so no work on the observatory.

However, I did pick-up a few bits to save time tomorrow. Bought a roll of wire mesh (18mm holes) to put round the edge of the base to prevent big wildlife taking up residence under the building. I intend to double this up to try and make the holes smaller, as mice can get through the tiniest of gaps, but not sure this will be effective for the smaller rodents. Also got a few drainpipe fittings so I can finish fitting the conduit connecting the pier to the warm room.

When the weather's lousy, preventing me from completing the fitting of the door, at least I can crack-on inside to take me closer to getting the floor down. ? 

Edited November 21, 2018 by Astrokev

[Astrokev]

Well, the weather's beaten me today. 

Went out mid morning to work on the door. Absolutely freezing, and the ground was soaking, so ended up covered in mud. Then it started raining. 

I got the door on, and it closes (still need to fit the keep in the frame). I'm not very happy with the gap between door and frame on the lock side. The problem is the thickness of the door, being about 75mm. To clear the frame as it closes means there is an inevitable large gap. Perhaps I should have bevelled the edge. 

I was cold, wet and miserable by the time I got to this stage, so decided to call it a day. Well, a morning anyway. If it improves significantly, I may go out later. 

I need to fiddle with it some more to improve the hinge fit, and to decide what to do with the gap. I could put an external strip down the edge of the door I suppose. Will give this more thought once I've warmed up!

Edited November 22, 2018 by Astrokev

[Dr_Ju_ju]

Hi Kev,

As you say there is bound to be a gap due to thickness, but get the hinged side sorted with the door freely open & closing, then adjust\plane\sand door to get an equal gap on top\opposite side to hinge.

Bottom will need to be adjusted for a weather bar, so can usually have a larger gap.

When the door is snug, you can add some sealant strip on the inside faces of the frame to block all drafts...

[Astrokev]

29 minutes ago, Dr_Ju_ju said:

get the hinged side sorted with the door freely open & closing, then adjust\plane\sand door to get an equal gap on top\opposite side to hinge.

Bottom will need to be adjusted for a weather bar, so can usually have a larger gap.

When the door is snug, you can add some sealant strip on the inside faces of the frame to block all drafts...

The gap on the hinge side is now parallel, although the middle hinge needs looking at. I think it's slightly out of line with the top and bottom. I could probably leave it as is, as it seems to function OK, but it niggles me. 

But, the gap on the hinge side is also narrower than the lock side, so to get them even either means packing the hinges out slightly to increase the gap on that side, or doing something on the lock side. The difference is not enough to warrant putting a strip of wood along the edge of the door on the lock side, but I may consider putting a strip on the face of the door which will cover the gap. 

Regarding the bottom edge, the gap is quite narrow. In fact I may plane a little off just in case it starts to rub with differential swelling of the wood. Although, with the weather as it is, it's likely the wood is already swollen to the max, so may not be a future issue. 

I also need to think how to seal the bottom. I was thinking of simply putting a baton on the sill behind the bottom of the door (similar to how the sides are done). Don't want anything too fancy, but any other ideas gratefully received. 

[Davey-T]

You can get galvanised  steel weather bar to set in the sill with matching cut out in the bottom of the door.

We used to fit thick doors as per sketch but may be too late for you now, still end up with a bigger than normal gap though.

Dave

 

 

[Astrokev]

In case my description wasn't clear (I was curled up on the sofa reading a Brian Cox book when I posted my last message), here's a diagram (not to scale) of what I'm considering to finish the lock side and cover the gap ie. add a timber strip onto the face of the door. This will also help give more protection from rain ingress. The weather is foul right now - I'll post some pictures when I can get outside without my thermals and arctic-weather clothing.

For the bottom edge, I'm thinking of using a simple stop across the back of the sill, but am open to other suggestions.

I also need to think of the top edge. Don't know whether to leave as-is, or put a narrow drip bar above the door to try and prevent water running down the wall and behind the door.

Gosh, doors are tricky things when you're making your own ? 

 

Edited November 22, 2018 by Astrokev

[Yawning Angel]

The 'Strip to cover gap' would also serve to protect the locking pin from direct attack - you might consider making it steel. If you prime it, it should take the Cuprinol Garden Shades well enough to blend in

[Astrokev]

4 hours ago, Yawning Angel said:

The 'Strip to cover gap' would also serve to protect the locking pin from direct attack - you might consider making it steel. If you prime it, it should take the Cuprinol Garden Shades well enough to blend in

Hmm, certainly a thought. 

To make it fully effective as a deterrent it would be no good simply screwing it to the door though! Would probably be best to put at least a couple of bolts right through the door with the nuts on the inside.

EDIT - or use one-way tamper-proof screws of course ? 

Edited November 22, 2018 by Astrokev

[Guest]

1 hour ago, Astrokev said:

EDIT - or use one-way tamper-proof screws of course ? 

Or countersunk allen key stainless bolts that would look fantastic against the paint and compliment your hinges.

I doubt a would be thief with come equipped with a set of allen keys ?

[RayD]

13 minutes ago, LeeRich said:

Or countersunk allen key stainless bolts that would look fantastic against the paint and compliment your hinges.

I doubt a would be thief with come equipped with a set of allen keys ?

If you use nyloc nuts on washers on the inside it wouldn't matter if they did as they wouldn't undo 

Edited November 22, 2018 by RayD

[yesyes]

Just in case, use a few different sized bolts

[Astrokev]

Weather was a bit kinder today -

I removed the door and realised that the middle hinge was rubbing on the frame, which was why I could hear a squeak every time I opened or closed the door. This was easily remedied.

Also took 1-2mm off the bottom edge to reduce the risk of it catching on the sill if the door swells in the future.

For the rest of the fit, I think I'm happy to leave the gaps as they are. The gap on the lock side is about 6mm - bigger than I would have liked, but this is caused by the thickness of the door and can't be reduced unless I bevel the edge of the door, which I don't want to do. Once the door is finally hung, I'll put a strip on the face of the door to cover the gap as previously discussed. The gap on the hinge side is about 3mm. I'm happy with this and its fairly parallel. Any variation in the width is caused by the frame not being 100% true I think, and not due to the door.

I also filled screw holes around the door edge and sanded sharp edges. Just waiting for the filler to dry then I can do final prep, paint and put it back up.

Also fitted the drainpipe conduit linking pier with the warm room. In my sad way, I've been looking forward to doing this so was nice to get this done. No idea what cables I may run through it yet, if any, but at least it's there if I need it!

As the light faded I started putting up mesh around the inner side of the floor joists to keep critters out. I'll continue this between remaining jobs on the door.

Edited November 23, 2018 by Astrokev

[Dr_Ju_ju]

Looking good, & I can guarantee you'll want\need to run some power\signal cable through the conduit....

One thought\question, looking at the pictures, is there enough of the floor studding exposed to support floorboards around each edge ??

[RayD]

Looking superb, Kev, loving it.

My advice is, if you can and have the space, put a second pipe under.  Run power in one and data in the other.  Small addition at this point but could save huge issues further down the line.

[Astrokev]

56 minutes ago, Dr_Ju_ju said:

One thought\question, looking at the pictures, is there enough of the floor studding exposed to support floorboards around each edge ??

A good question. I think so - there's 10mm on all edges. Doesn't sound much but I've been using this to support spare MDF boards to stand on while I do the build, and they've been absolutely fine. In fact I've been using these to support step ladders and they haven't let me down yet  

When the floor is down, the closest I'll be standing to the walls is probably on top of the lateral joists so I don't think the very edges will need to support any significant weight, certainly nothing heavier than I've already tested. 

Hope I don't have to eat my words here ?

[Astrokev]

1 hour ago, RayD said:

Looking superb, Kev, loving it.

My advice is, if you can and have the space, put a second pipe under.  Run power in one and data in the other.  Small addition at this point but could save huge issues further down the line.

Arghh!

Why do you suggest this Ray? I presume it's not just for extra space, so guessing it's due to possible interference?

To be honest I was anticipating having the laptop next to the scope since getting the thing focussed with the lappie in the warm room would be tiresome. But then I saw Lee's idea of having a second screen next to the scope....

Edited November 23, 2018 by Astrokev