zoothorn Posted May 15, 2020 Author Share Posted May 15, 2020 @Onoff so what all of 2 mins? I spent ages/ trawled pages w'search box! slope ground work log cabin etc etc. Youre just more adept using it/ know what build lingo likely then (& not being thick is a major headstart too). Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 (edited) @PeterW &/ or @Onoff could either of recall your suggestment for my roof? IE going an insulated layer, & osb was it ? so at the moment what I have/ what I pulled off the cabin when decontructing it.. is just t&g 20mm pine sections. Can you remind me of a better plan, maybe using 25mm PIR & 11mm osb? (no need for 50mm & I'm concerned with added weight of 2x 18mm osb sheets). I'm in a major rush too as I need to add to order (plasterboard etc) that's being delivered asap > tmrw!! sorry I will try to find the suggestion now.. but any reply in meantime really helps! cheers zxoot. Edited May 21, 2020 by zoothorn Link to comment Share on other sites More sharing options...
PeterW Posted May 21, 2020 Share Posted May 21, 2020 Sorry where is the 2x18 OSB..? And are you talking internally lining the cabin...? Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 2 minutes ago, PeterW said: Sorry where is the 2x18 OSB..? And are you talking internally lining the cabin...? Hi Peter, thx for such a quick reply. Just googling 'insulating a cabin roof' & some photos shows 1) adding PIR onto my t&g roof (as it is), then 2) osb layer on top > 3) felt over presumably).. & wasn't your suggestion somewhere similar? thanks- zoot Link to comment Share on other sites More sharing options...
PeterW Posted May 21, 2020 Share Posted May 21, 2020 You'll need to edge that with timber but it should work fine. If it is solidly supported by insulation then you could get away with 9mm OSB Where are you introducing 2 layers of 18mm OSB..??? Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 3 minutes ago, PeterW said: You'll need to edge that with timber but it should work fine. If it is solidly supported by insulation then you could get away with 9mm OSB Where are you introducing 2 layers of 18mm OSB..??? I had thought you recommended 18mm osb for the top layer, back wherever the post is. Not so? good. No 18mm then. 11mm osb3 top layer. Ok so just 'edging with timber' to consider then: so I have two 'end/ edge' profiles of osb top & the btm layer of 20mm t&g I assume this timber attatches to.. but these edges hardly ideal to whack screws or nails into, especially the osb-? Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 Anyone know if ground below my base -must- have some sort of weed barrier? Since made end of summer last, all I have is some tall grass coming up thru/ easily cut. Once i have floor on including front deck bit, light will be diminished alot, & I can get under & cut it from the low side with a long blade I guess. Or just spray weedkill when neeeded? I wonder if this growth will naturally just be kept in check being mostly dark underneath. Logistics & expense of a weed layer are ~big I think. thanks. Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 4 hours ago, Onoff said: So how else do you propose killing knotweed growing on stream & river banks here then-? roundup? pull it out? you have no idea Onoff. I have had to or my property would be infested with it by now. And neat glyphosate too is only thing that works, 15x stronger than 'roundup' too (which is all grass needs/ all what I was proposing to use)! Its not next to a stream, the tricky areas I'm mainly talking of ~5m from it. And just needs a weak roundup even @ 50/50 for just grass: I'm not the slightest bit concerned about anything significant at all getting into the stream with the idea. Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 Can someone help with what to do with my osb edges, & fixing my PIR: The 3x2 will have a sandwiched layer of osb3 between it & my base, so this edge will be prone to rain. What's best to do? And the PIR 50mm which will be within the outer 3x2. I may have to leave it/ tarp this sub-floor work (trying to get overhanging ash cut before I put cabin up.. not easy with lockdown/ maybe not possible) so should I fix it to the osb I wonder.. soudal LE foam 'dabs' maybe? thanks zoo-t Link to comment Share on other sites More sharing options...
Onoff Posted May 21, 2020 Share Posted May 21, 2020 Do a sketch? Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 1 minute ago, Onoff said: Do a sketch? Sorry, a sketch of 3x2 ontop osb? not sure if it would help, even one of yours tbh. plus my camera's rip. Its simply the fallible edge of the osb.. what is usual to 'cover it' to the elements? Ive thought if I extend the 3x2 out so it hangs 1" over edge of the osb, that will hide it a bit- but it'll still get wet surely. (my other Q: shall I soudal-foam fix my PIR to the osb? I need to fix it down really). Link to comment Share on other sites More sharing options...
Onoff Posted May 21, 2020 Share Posted May 21, 2020 (edited) I meant a sketch of the planned build up. Remind me, what sits on top of this frame: Edited May 21, 2020 by Onoff Link to comment Share on other sites More sharing options...
zoothorn Posted May 21, 2020 Author Share Posted May 21, 2020 (edited) @Onoff Ok so where there are single nogs/ the 2.4m square for the cabin: osb (11mm) will cover to the edge of this (^) base. Then an outer square of 3x2 (IE, the cabin's 4 walls go upon this). Within this square 3x2 'frame' : the 50mm PIR. Edited May 21, 2020 by zoothorn Link to comment Share on other sites More sharing options...
zoothorn Posted May 24, 2020 Author Share Posted May 24, 2020 Hi- does anyone know if these osb edges can be covered/ or, what's the best thing to do here? The 11mm board edges will be exposed to weather you see I need to sort this before I can proceed. Osb3 will lie onto of this (^) base. A periphery square 'frame' of 3x2 will sit ontop of the osb. 50mm PIR will go inside the 3x2. Thanks, zH Link to comment Share on other sites More sharing options...
Roundtuit Posted May 25, 2020 Share Posted May 25, 2020 Why not put the insulation into your existing structure? Not sure what the osb will be adding tbh. Link to comment Share on other sites More sharing options...
Onoff Posted May 25, 2020 Share Posted May 25, 2020 11 hours ago, zoothorn said: Hi- does anyone know if these osb edges can be covered/ or, what's the best thing to do here? The 11mm board edges will be exposed to weather you see I need to sort this before I can proceed. Osb3 will lie onto of this (^) base. A periphery square 'frame' of 3x2 will sit ontop of the osb. 50mm PIR will go inside the 3x2. Thanks, zH As ever, without a sketch its hard to visualise but you could cover the OSB edge AND the vertical side of the 3x2 frame with a sacrificial strip of softwood treated against the elements. Or a strip of aluminium, upvc cladding etc. Is it / will it be possible to remove the board cladding the bottom of the cabin? Thinking to maybe staple on a wrap of DPC (damp proof course, available in rolls very cheaply), so it sits up under the bottom board and comes down over the OSB edge and 3×2. Your "sacrificial" strip of treated softwood goes over that. Not shown, the strip of sacrificial softwood. Shown (dashed), the DPC up behind the bottom board coming down over the OSB edge. (Excuse sketches, hungover). Maybe you could get the DPC up in the groove of the bottom board. I don't know if you're intending putting OSB over the whole deck? I would be doing so but just where the cabin sits. I'd also leave a gap where the walkway is so it doesn't butt tight up to the cabin or it'll be a Mecca for rot! That bottom cladding board, on the walkway side will suffer from rain hitting the deck and splashing up at least 6". I'd treat it with black bitumen paint or similar periodically. Has this cabin got a floor with it? How are you going to stop the pir dropping or will it just sit on the base frame you've already built? As ever, many ways to skin this (next door's) cat! Link to comment Share on other sites More sharing options...
zoothorn Posted May 25, 2020 Author Share Posted May 25, 2020 Hi @Onoff cheers for thesees sketch (calming!). Two discrepencies: the Osb goes below the 3x2 & PIR (I think this is how PeterW suggested/ this subfloor his idea). But your idea I think remains the same (& sprung to mind over w'knd) of adding a side to cover the osb edge. And the t&g in your 1st sketch is the wall, not cladding (I dont have an inner load-bearing wall) & so sits upon the 3x2. So any dpc will need to do another 90*. If its thin enough a dpc can maybe squeeze between the cabin floor & wall.. but any thickness & it'll then prevent a tight join between them & stick out sideways.. and/ or onto the 3x2 as well. But if thin & able to be bent 90* out > then 90* down over the osb edge = bingo. Not sure. Yes a floor is with cabin: not great but useable: 3 interlocking sections (2x1 battens with floor slats nailed across ontop) slide together making the floor. So it has double-use: a floor obviously & a 'start' section, to position walls tight around > & build up. Sorry even if I could sketch.. I don't have a cam now to photo it. Thanks alot- zoot Link to comment Share on other sites More sharing options...
zoothorn Posted May 25, 2020 Author Share Posted May 25, 2020 @PeterW hi Peter if you're out there.. was your suggestion like Onoff's 1st sketch.. to put the PIR directly onto my (^) base, within the 3x2 perimeter frame (so this 'frame' sits directly onto the base) >>> THEN the osb covers the lot? [Or Osb goes 1st onto base..). Thanks zoot. Link to comment Share on other sites More sharing options...
PeterW Posted May 25, 2020 Share Posted May 25, 2020 What @Onoff said and drew is how I would do it. I would do a full deck of OSB below the 3x2 if possible to stop stuff trying to burrow into your insulation. Then I would do exactly what was suggested or staple the DPM on the top surface, staple and then wrap down over the edge of the OSB and staple again - Frame will trap the DPM and then a trim piece over the lot will tidy it up. Link to comment Share on other sites More sharing options...
zoothorn Posted May 25, 2020 Author Share Posted May 25, 2020 (edited) 49 minutes ago, PeterW said: What @Onoff said and drew is how I would do it. I would do a full deck of OSB below the 3x2 if possible to stop stuff trying to burrow into your insulation. Then I would do exactly what was suggested or staple the DPM on the top surface, staple and then wrap down over the edge of the OSB and staple again - Frame will trap the DPM and then a trim piece over the lot will tidy it up. Ok understood. Thanks for confirming. So when the suggestion is a 'dpm' all I recall is that stiff black rigid textured stuff that comes on a 6" wide roll.. which I can't see how malleable enough to pull over a sharp edge. But is the suggestion a -sheet- over the whole expanse of the osb? does that mean then the same type of plastic DPM (thinner than this rigid textured roll stuff) laid under my extention floor concrete top (poking up I bent up & trimmed then laid PIR on > caber floor): is this what you have in mind? Or maybe the thinner 'vapour sheet' stuff suggested on topside of my ceiling pB (which I can't face doing!)? not sure if this was a 'DPM' per se. thanks, zH Edited May 25, 2020 by zoothorn Link to comment Share on other sites More sharing options...
Onoff Posted May 25, 2020 Share Posted May 25, 2020 (edited) DPM - damp proof membrane, big (blue in my case) sheet that went under your concrete. DPC - damp proof course. Comes in roll 6" wide or more. Likely a thicker gauge than dpm. This is the stuff I meant. You can get a plastic, embossed type or a thicker rubber type. It should bend OK. If you're capping over it with timber you could equally use strips of the thinner DPM under your slab. Ffs you could use rubble bags cut up! Tbh though a dpc is a dpm. "Course" just meaning it is incorporated in a wall. Traditionally this was slate, pitch etc. No the suggestion isn't a big sheet over the whole lot! Edited May 25, 2020 by Onoff Link to comment Share on other sites More sharing options...
PeterW Posted May 25, 2020 Share Posted May 25, 2020 Sorry !! Both known as DPM round here - sheet and roll ..! I mean roll - get a cheap 12” roll and it will bend over the edge no problem. Just fit your trim board and cut the excess off. Link to comment Share on other sites More sharing options...
zoothorn Posted May 25, 2020 Author Share Posted May 25, 2020 45 minutes ago, PeterW said: Sorry !! Both known as DPM round here - sheet and roll ..! I mean roll - get a cheap 12” roll and it will bend over the edge no problem. Just fit your trim board and cut the excess off. Ok thanks chaps- so not a sheet but a cheapo DPM/ in DPC width.. now this is all I see at screwfix: the very stuff I think is too thick to do a sharp 90* down, after I staple it to the horizontal outer 3" of the osb under the 3x2 'frame'. https://www.screwfix.com/p/capital-valley-plastics-ltd-damp-proof-course-black-30m-x-150mm/78665 I can understand if the suggestion is thin stuff (for eg, same guage as my placcy dpm under my concrete) but not thick DPC stuff that's lain under concrete block course. The screwfix stuff folks say is extra-thick too. I had a roll of this, & its like 1.5mm thick. Could you possibly provide an eg of what you suggest? or is it just this ^. I only have screwfix or toolstation to get this tmrw AM. I must fit this sub-floor tmrw. thx zoot Link to comment Share on other sites More sharing options...
PeterW Posted May 25, 2020 Share Posted May 25, 2020 Toolstation - cheap as chips and does bend ..! Stop worrying and JFDI.. Link to comment Share on other sites More sharing options...
zoothorn Posted May 25, 2020 Author Share Posted May 25, 2020 4 minutes ago, PeterW said: Toolstation - cheap as chips and does bend ..! Stop worrying and JFDI.. So are you suggesting this? https://www.toolstation.com/damp-proof-course/p54162 And suggesting bc you know its thinnner than the textured stuff at screwfix? Its JFDI yes its p'easy a 5m job.. once Ive got the right stuff. Until then its hours to trawl/ ask/ ask again etc to establish what it might be. Link to comment Share on other sites More sharing options...
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