I was going to start a thread about a similar thing and then stumbled upon yours
@dlockers. I'm in the very early stages of convincing myself that I need to rip down my existing cabin and DIY a new one entirely. I have what I believe to be a Dunster cabin, or something of very similar construction. We inherited it when we moved in. It is solid 45mm tongue/groove stuff which slots one over the other. 4.5 x 2.5 ish metres. It's solid. Good roof. But it's seen better days and is rotten around the lower door frame and some of the floor. Sadly, the previous house owners that built it or had it built, decided to lay it on the bare garden (some shingle and mud). Inevitably, someone jumped through the floor earlier in the year after throwing a good darts score.
The problem with the Dunster style cabins are that each timber expands and contracts in the seasons and it moves. So you can't really take them seriously as structures as you can't attach anything to the internal "walls" as they move. So you can't really batten and insulate without the structure being at war with you. They are cabins to remain as summer houses/sheds really.
I want to pretty much build the cheapest replacement I can. I am limited in size as have a very small garden so needs to be similar to 4.5 x 2.5. I say cheap... I mean without scrimping on the important things like...ya know...it not rotting. Solid and well insulated. Also needs to be within 2.5m total height as right up to boundary. I only really want a door and a single small window as it's primary function is a home office and storage as we have no garage (converted to bedroom).
I've watched countless videos on the matter and to get going, I've been debating the two main factors which will account for all the plans. The base and the roof construction. I'm definitely going to build all 4 walls the same height, then use firrings to raise the front side to keep it as simple/quick as possible.
Some questions...
Where do you buy giant tarps and how much are they? My main concern with these projects is that we live in the UK where it rains daily. The chipboard floor you used I would have been worried about that swelling up. In fact I see a lot of people use OSB for the floor or even ply in case of water issues. What made you chose the tongue and groove chipboard? Cost? I feel like I'd be constantly rushing to not have things get wet and have nowhere to store stuff whilst it will be in progress.
In terms of the base, mine will be small and the ground is already very flat. I like the idea of the screw/rods method you used, but I just feel like it's a faff compared to just pouring a concrete pad? What's the cost difference? I see more people doing raised timber ones and celotex on youtube compared to a concrete pad. I tend to see concrete pads more with brick/block builds.
How much gap did you leave from floor to the base timbers? I read that it should be 15cm to minimize splash back from rain?
I understand how to do the risen timber floors and that air flow prevents damp with the PIR and tape creating a seal. But I don't really get the damp proof membrane vs damp proof course situation with using a concrete pad and just having the timber floor sat on top of it. Seems different methods can be used to prevent water wicking up the base.
What have you decided on hot vs cold roof? I understand pros and cons of each but I think it will depend on my base choice first affecting height.
Any ideas on predicted total cost and time? I gather EPDB roofing can't be applied with the glue when it gets uber cold come say October.
Why do you feel a steel lintel is necessary? (Not saying it isn't).
Are places like Wickes pointless for decent timber at good prices? I find a lot of the CLS is heavily warped at my one.
You refer a lot to a "build pack" but I can't see where you state what this is, where from and how much it was. Is it some sort of kit from a supplier with a load of timber for this kind of project?
How did you get a 70KG Rubber roof up a ladder by yourself?
@Welshman that's interesting about the method to tie down the roof hangers with a single screw. Why is this not publicised more on youtube builds? I see literally nobody doing this. Looks about 100 times quicker? The more I think about it though,
@dlockers makes a good point that the forces to resist are in line with that method. A hanger would have multiple nails going in perpendicular to the force generated to lift the roof. I guess hanger is both traditional and therefore preferred, plus cheap. It's just unfortunately slow AF.