Insulating log cabin floor.

[Firetrap999]

Just finished assembling 44mm log cabin for use as an office, a little perturbed by some comments on this site suggesting log cabin kits are a waste of money and that you should build your own from scratch. My main concern is keeping it warm enough to work in and damp free. The roof is insulated with 40mm kingspan provided by seller and the doors and windows are double glazed. i have raised the cabin on a decking raft (4") and insulating the floor voids (6" deep) with polystyrene packing chips (free waste product), but supply running low may need to think about something else. Advice please on;
1. What else can I use to insulate floor?( base is concrete and some areas sand between concrete strip footings).
2. Is this likely to be insulated enough if I include an electric heater?
3. Would the cabin benefit from a fan / ac unit or de-humidifier?
4. Any further related guidance always welcome thanks in advance.

 

[mattylad]

How are you now going to insulate the floor if you have build/erected it?

And is it really a log cabin? Or is it a shed that is just called a log cabin?

 

[Firetrap999]

The log cabin kit allows for the floor to be put in last, I am screwing the 19mm t&g so I can lift if needed without causing damage if I have damp problems. So far I have put about one quarter of the boards down and after viewing this site decided to get advice.
In answer to your last question, you call it a shed, my father in law calls it a chicken coup, i call it a log cabin, because that is what it is advertised and sold as. the term "log cabin" might not be a true definition in the true sense, however, the term is a generic term which is used synonomously to describe those outdoor structures assembled by interlocking "planks" if you like.
Does it really matter and does it have a bearing on the question or response? No
Thanks anyway

 

[mattylad]

Actually yes it does have a bearing on the question.
Do you know how the floor is fitted in a real log cabin? lol

So its a shed called a log cabin - OK fair enough.

If you fit the floor in this last how much space is underneath? can yu fit 50mm kingspan down there? That would help insulate.

 

[Firetrap999]

I have raised the shed on a 4" decking raft and with the 2" base gives me a 6" void, however this is totally enclosed and not ventilated. water is diverted away from the shed with guttering and DPC membrane to soak away so i dont anticipate water creaping in. However, if i fill to 6" with insulation will it still potentially cause damp?? I am thinking maybe leave a 2" gap and drill holes in base to allow a bit of airflow, I might be over worrying but i want to get it right and value any input, from those who are more knowledgable than me as a beginner. Thanks.

 

[ladylola]

I think you've answered your own question there with what do do.
Fit kingspan as matty suggests leaving a space between that and the ground and vent that space not forgetting to cover the vents on the inside with insect mesh.

 

[Firetrap999]

Lola thanks for your feedback, interesting, I was going to leave the gap between the boards and the insulation to stop the boards sweating but you suggest raising the insulation off the ground and venting that area, I guess it will invlove a little improvisation to raise the polystyrene beads (could use a net or weed fabric and the kingspan only needs to be held with four nail supports), that way i guess the cold air stays next to the ground. sound advice, thanks.

 

[mattylad]

With that much room you could use 100mm kingspan.

 

[Firetrap999]

yes i suppose the more the merrier. 44mm. log is advertised as adequate for office accomodation, i will have to see once I am using it how warm it is, and then modify or adapt as needed.

 

[rmwebs]

Sorry for the potential hijack here but could I just ask firetrap, for the kingspan, was 4 nails enough to hold it up? I'm about to start building one of these myself and was wondering what the best method of raising the insulation up would be.

Also, did you come across any decent way of getting air under the insulation?

Finally, if you've got any photos please do share them!


Cheers!

 

[Firetrap999]

Decided to leave gap at top as I cant ventilate below what will be pea shingle covering the wooden raft. I have taken big steps to ensure no water gets under cabin and will keep my eye on moisture under boards before fitting out. Hope this helps.

 

[rmwebs]

Thanks firetrap, so you've basically got your base, followed by a membrane, then the wooden base/beams, then insulation, then the floor, correct?

Just want to make sure I'm not going to screw up

 

[Firetrap999]

4"x 2" raft (base) to raise cabin, 2" cabin bearers giving a 6" gap under the floor.