Chris's Obsy build

[Chris]

totaly brill and the edging looks good too

Thanks Shellfish:) I'm pleased with it so far, I'm going to put some weed membrane down where needed and lay a thin layer of slate chippings down around the slabs for both aesthetics and to keep the neighbours cats from doing things in the sand, I don't think they would like digging in sharp pieces of slate:)

[laser_jock99]

Hi Tinker, good question:) I've been trying to decided if I need to as the slabs are spaced for ventillation to keep the timbers dry, and the timbers are tanalised and pressure treated, plus I'm going to creosote them. I wouldn't mind adding damp proof as well, one question though if I wrap damp proof around the timbers where they come in contact with the slabs how should I attach it? I don't want it to back fire and trap moisture against the timber? I was thinking maybe stappling and then running silicon sealant aound the seem, not sure if it sticks to wood though?

I used slices of plastic (from 5L chemical bottles) between my floor joists and any supporting concrete blocks. The concrete acts like a sponge- best to put a barrier between that and your timber.

[dtr42]

you could put denso tape[water proof tape] on the wood spars that touch the slabs but apart from that i wouldnt felt the bottom as you want airflow and as it is already treated you probably wont get damp .[damp in brick is capillary action or ventillation problems ] not sure if a treated wood would absorb water and with good airflow under your observatory there realy shouldn't be damp problems

ps forget the denso tape it's realy expensive 17 quid for 10 metres [i get it for nowt from my work ]

[Chris]

Thanks guys I agree it might be best to place a barrier just purely between the slabs and where they touch the timber and not wrap it all the way around.

Cheers:)

[nightvision]

This may be of interest; when some deck installers fix a joist to a house wall they use galvanised or stainless bolts and have several nuts as spacers between the joist and wall to stop moisture retention/passage. You could do something similar to lift the joists off the slabs but I don't think it's required.

[malc-c]

Just purchase a small roll of the wide DPC normally used on brickwork, cut a length just over the width of the slabs and staple / tack them to the underside of the timbers so that they are sandwiched between the framework and slabs.

[Gina]

Just purchase a small roll of the wide DPC normally used on brickwork, cut a length just over the width of the slabs and staple / tack them to the underside of the timbers so that they are sandwiched between the framework and slabs.

Yep. That's what I did With the DPC going up the side of the timbers and fixed there so as to retain the integrity of the DPC between concrete and timber.

[Tinker1947]

A long time back i built a Workshop, much the same as your design, i use rubber mats that the railway put between the sleeper and chair (this is the bit the rail goes in) there were more to act as a cushion, so i would still find something as its not expensive and will stop any sort of damp rising even normal 9" DPS would work, if your live near to me i have a half roll all you need do is collect...

[earth titan]

Hi Chris.

I've placed a length of the plastic DPC you buy on a roll on the top of all of my external woodwork. As the woodwark is inside the cladding I've used, the DPC 'lips' over the woodwork and the water 'runs off' and away from the brickwork base (I didn't take a photo unfortunately). The bricks won't wick too much and with the rain we've recently had, I can report the wood is all dry so far. If you've gone for treated timber it should last many years as long as it doesn't stand in damp or wick.

Place an overhanging length on top of each of the 'piles' and this should be fine.

[Islander]

Yep. That's what I did With the DPC going up the side of the timbers and fixed there so as to retain the integrity of the DPC between concrete and timber.

This is the way my wooden shed is built and will be the way my obsy will eventually be built. The DPC is cheap and it does the job

[Chris]

Ok thanks guys DPC it is:) so slighlty larger than the slabs and fixed to the under side, and based on what Earth titan as done I can look if DPC would be of benefit on other aspects of the obsy:)

Night vision, that sounds like it would be very effective for stopping the damp, would the small surface area of the nuts crack the slabs though with pressure=force/area?

Tinker, your probably a bit too far but I very much appreciate the offer though:)

Thanks all:icon_salut:

[malc-c]

DPC has a 1001 uses - I used some as Tom described, to help make a seal on some exposed joints of the roof, and to provide a skirt to the roof so that it clears the door to the warm room

[earth titan]

DPC has a 1001 uses - I used some as Tom described, to help make a seal on some exposed joints of the roof, and to provide a skirt to the roof so that it clears the door to the warm room

Same here. DPC provides a flexible seal at the roll off joints on my build.

[Chris]

Slabs mortored in and levelled within an inch of their lives.

Shed delivered, to recap it was a slight second thus reduced bigtime, I've only found a couple of knot holes in the base which are now filled so looking good so far:)

I have 5 extra tanalised 6"x2" timbers for the base which now have their first coat of Cuprinol, I went for 'Ducks back' Cuprinol which has wax in it, looks like good stuff.

I've also bought some damp proof sheet, and some 90mm turbo screws to help attach the base (which itself has 2"x1" longitudinally) to the 6"x2" timbers width ways, I've not fully worked out how best to attach them, not much contact area so I might have to add some more treated timber.

[Chris]

I managed a fair amount this weekend, I cut the hole in the base for the pier and gave the base 2 coats of stain, and 3 coats on the 6"x2"'s

I've covered the 14 pabs with DPC, layed the 6"x2"'s, and got some help from my father in law with getting the base down over the pier and erecting the 4 sides. I've temporarily fixed the roof with a hand full of screws and covered it over with tarpaulin as I'm not going to felt the roof until I've figured out the mechanism for the roll off roof? This is one of my next challanges along with pulling my finger out with the pier adapter:D

Theres a couple of issues with the slight second shed, 1) quite a few wood knots have fallen out so I've got a fair amount of filling to do, 2) the right wall panel is not particularly square so when everything was screws together its pulled the front right corner off the pad by about 8-10mm, I'm going to leave it a few days to see if things settle if not I might have to shim that corner, the rest is nice and flat and square at least:)

[samtheeagle]

Awesome progress Chris, you must be very pleased

[Chris]

Thanks Sam, yes it was very nice to see all the walls up, I did take a step back to just take it all in and grin at it for a while:D

[malc-c]

Coming along nicely Chris.

Have you any ideas on how you are going to modify the roof section so it rolls. From the images it's going to take a fair amount of strengthening

[shellfish]

Looks fantastic. I realy hope you stopped at the end of the day and sat looking at it with a beer and emence pride

[Chris]

Coming along nicely Chris.

Have you any ideas on how you are going to modify the roof section so it rolls. From the images it's going to take a fair amount of strengthening

I'm going to have to stick my thinking cap on Malc:), I'm not sure about the role of system yet but one things for sure, by the time I've strengthened the existing roof panels its going to be a fairly heavy roof. One option is to make a new light weight roof out off insulation board and Coraline and find a use for the timber from the existing roof panels such as building the warm room partition and a work bench, I don't like waste:D

I'm thinking of strengthening the obsy maybe with some right angle steel and some more timber, I have to say that without the roof the frame was more sturdy than I thought it was going to be, not sturdy enough though:)

[Chris]

Looks fantastic. I realy hope you stopped at the end of the day and sat looking at it with a beer and emence pride

I did indeed shellfish, a brew instead of a beer though:)

[Petrol]

Hi Chris, Great progress so far. I hope you don't mind me saying that if I were you, I would cut back the excess DPC between the pad stones and the joists. If the DPC overhangs the obsy, water will wick up the joists and they will rot. Preservative is great but timber cannot stand being wet for long. Whilst my roll off is tiny compared to your project, the same principles apply. This is how I fitted my DPC between the joists and the pad stones.

Just a minor point but a few minutes trimming back now could save you problems later.

Regards,

Pete

[Chris]

Hi Pete, thanks yes I'm going to pin the DPC to the underside similar to what Malc, Gina, Tinker and youself have done:) I'm just trying to figure out something, have you sealed around the edge of the DPC so moisture doesn't get trapped between the DPC and the timber or is this unlikely to happen? I'm hoping the tanalised timbers will help with rot but like you say the more preventative measures the better:)

[yesyes]

have you sealed around the edge of the DPC so moisture doesn't get trapped between the DPC and the timber or is this unlikely to happen?

This is exactly what I was wondering...

[Petrol]

Hi Pete, thanks yes I'm going to pin the DPC to the underside similar to what Malc, Gina, Tinker and youself have done:) I'm just trying to figure out something, have you sealed around the edge of the DPC so moisture doesn't get trapped between the DPC and the timber or is this unlikely to happen? I'm hoping the tanalised timbers will help with rot but like you say the more preventative measures the better:)

No it's not sealed. Since the DPC / timber joist is covered by the obsy, it won't get wet from above. My concern in your case was quite a bit of DPC sticking out and water running along the DPC and into the joist. The purpose of a DPC is to stop moisture rising from the ground.

Bit of theory that might shed some light on it.

Timber only rots when the water stagnates. If you throw a piece of wood into the sea it won't rot. Drive a wooden stake into the ground and it will. Just try to keep the load bearing timbers dry Tanalised timber makes a huge difference though and if you are doing what others have, you will be OK.

Hope that helped

Best,

Pete