Workshop design questions

[gav]

Having completed the groundworks for my workshop build I am now looking at some of the finer details of the construction which is based around the design of mailee who kindly sent me plans of his build.

I have a couple of questions

1. The floor will be timber with kingspan ployurethane insulation boards (from the seconds company recommended elsewhere) I was originally planning to lay these flush underneath the floor surface but the other day I was watching challenge tommy walsh (I know someone has to! ) and they were doing the one with the well in the middle of the floor. They insulated the floor using the same material but they said on the programme that they needed to leave an airgap between the insulation and the floorboards. Is that necessary?

2. I think I've understood the wall construction of inner lining, vapour barrier (plastic sheet), insulation, breathable membrane and outer cladding.
Would this http://www.screwfix.com/search.do;j...KCSTHZOSFFY?_dyncharset=UTF-8&fh_search=98160 be suitable for the breathable membrane layer? And should you leave a gap between this and the cladding, I'm planning to use shiplap boards?

Gav

 

[Anonymous]

Hi Gav,

I'll be interested to hear what people have to say about the kingspan. I'm about to do the same.

As for the breathable membrane there are a number of people who haven't bothered using it. My plan was to ensure there is space for air to circulate and escape from the cavity walls. This will stop the condensation forming and giving me grief.

Dave

 

[druster]

I've used similar stuff on wall construction before, as recommended by architect, but what do they know eh?
With regards to floor insulation, I have been told that it should be tight up the floor, with air gap underneath.

 

[The Bear]

I have put polyurethane insulation sheets between between the joists in the dining room of my Victorian house. On builders advice the top of this is flush with the bottom of the floor boards. Under the polyurethane is well ventilated by the air bricks. This has been in some time now and I have had no problems with condensation, damp etc. Despite having stripped floor boards and an open chimney this is now the warmest room in my house.

Mark

 

[ByronBlack]

I've used the black stuff from screwfix you linked to and after a year it's fine, so I would say go for it. As for floor insulation - is it really needed? I didn't bother on mine and have not ever felt that the floor is too cold or the workshop is suffering for it, how much heat is lost through the floor?

 

[Waka]

When I did my WS floor a couple of years ago I laid the 2" insulation on a concrete floor, this was flush with the floorboards. I've experienced no problems with the floor at all.

I also did the same with the walls, for the ceiling I used 6" rockwall insulation coverd with plasterboard.

To give you an idea of the benefits, I didn't need any additional heating in the shop last year. having said that in Dorset our winters are not as severe as other places in the UK.