Workshop Design

[defsdoor]

As for the DPC ... I was just following Mike Garnham's design which shows both:

build-a-shed-mike-s-way-t39389.html

The DPC on that diagram is between the blockwork and the sole plate - which is part of the timber construction. On yours isn't it between two courses of blockwork ?

 

[kingcod]

As for the DPC ... I was just following Mike Garnham's design which shows both:

build-a-shed-mike-s-way-t39389.html

The DPC on that diagram is between the blockwork and the sole plate - which is part of the timber construction. On yours isn't it between two courses of blockwork ?

Yes correct. I have tweaked the design. I did this because I hadn't done enough planning to use straps set into the concrete to hold down the sole plate (and also thought it looks a bit flakey as a way of holding something down). I wanted fasterners fixed directly through the sole plate into the blockwork .. but clearly I can't do this with a DPC in between as it would puncture the DPC. Hence the DPC set one course down. Its still got above the 150 mm ground clearance you need for a DPC.

I hope this is all going to work out as the timber arrived so the sole plate goes in tomorrow!

 

[defsdoor]

Is that ok like that ? (I know nothing but read all the workshop build threads as I have a small brick shed at the bottom of the garden that I would like to make bigger at some point)

With the dpc underneath the sole plate, which is firmly fixed into the course below, I'd feel more confident that things couldn't move.

 

[johnf]

Well for whats its worth in my opinion the DPC should be directly on the concrete slab witch should be 150mm above the surounding ground level in this situation there is no need to put a DPC below the sole plate just bed the plate on with mortar and fix with masonry fixings or screws when the mortar has gone hard.
In 45 years trading as a building contractor I have done loads of buildings like this and no problem with any of them.

 

[kingcod]

John - since the ground is on a slope (you can't really see on the pics) the slab is down to ground level at one end and way up around 150mm above ground level at the other end - otherwise I could have done as you suggest.

I'm still mulling over what to do with the DPM where it appears out the end of the slab ... I am not sure cutting it off at this point would be a good idea as I assume I'd get damp ingress into the concrete slab. Should it be up round the sides fo the block in some way?

 

[johnf]

John - since the ground is on a slope (you can't really see on the pics) the slab is down to ground level at one end and way up around 150mm above ground level at the other end - otherwise I could have done as you suggest.

I'm still mulling over what to do with the DPM where it appears out the end of the slab ... I am not sure cutting it off at this point would be a good idea as I assume I'd get damp ingress into the concrete slab. Should it be up round the sides fo the block in some way?

Kingcod If you mean the dpm below the slab you can do as you sugest but if its exposed to weather and sunlight it will eventualy fail

 

[kingcod]

I'm having a think about cladding insulation and all things to keep warm, toasty and dry in the workshop.

I quite like the look of larch featheredge cladding as a cheaper alternative to oak.

The advice I have read so far for featheredge seems to suggest the need for Tyvek or similar underneath the Tyvek to keep out wind and expel moisture. Then there is the additional suggestion of a vapour barrier on the inside of the building just below the plasterboard. Looking at my diagram of all this below is two vapour barriers overkill or are they doing slightly different jobs? If so whats the cheapest material I can use for the vapour barrier or is there a hard to avoid industry standard

For simplcity the diagram doesn't show the timber frame.

 

[JanneKi]

That's the right way to do it actually, but you have to ensure there is enough ventilation space between the Tyvek and the actual cladding. Why use larch, that's expensive stuff (at least here in Finland)? Tyvek and the vapor barrier actually do different things:
- vapor barrier keeps moisture out of the insulation, by not letting (the presumably warmer and moister) air enter the insulation.
- Tyvek lets moisture (in gas, i.e. moisture in the air) OUT, but does not let water (in it's liquid/solid shape) enter into the insulation.

In Finland (and Sweden) we user normal spruce/birch for the cladding, but we paint it then (usually). That works pretty well, even with Latex paint - AS LONG as you have sufficient ventilation gap BEHIND the cladding, typically minimum of 20-20 mm - of non-restricted air flow. In certain sense that is a fire hazard, but it required to keep the cladding healthy - paint cracks eventually and the moisture that gets into the wood can ventilate/dry out from the non-painted backside of the wood.