Insulated Log Cabin

[Borris-Bear]

We're looking to install an insulated log cabin in the garden and were looking at the Dunster House range of insulated cabins.

something like this - https://dunsterhouse.co.uk/premiumplus-severn-w5-0...

They claim their 62mm logs with 30mm polyisocyanurate insulation is the equivalent 0f 140mm logs with a u value of 0.57 W/m2K. Is this good?

Does anyone have experience of these products and can verify that they are useable all year round?

thank you

[Basil Brush]

I can't help specifically on that one but I have a 40mm wall thickness double glazed Tuin cabin, with 100mm insulation under the floor and 75mm sandwiched in the roof and it didn't need much heating even when well below zero outside.

[LJF_97]

Approved document B requires a U-value of 0.18, so no, they don't perform particularly well.

Will it be usable all year round? Depends on if you want to pay to heat it.

[trickywoo]

I’ve got a shiplap 19mm with 50mm celotex everywhere except one long side which is all single glaze.

I do have a 5kw log burner in it but it doesn’t need that much heating. It stays cool in the summer.

You just need to remember regardless of the amount of insulation you have structures like these will revert to ambient quite quickly once you remove the heat source because they have very little thermal mass, practicality none compared to a house. What this means is that if you turn the heating off at say 5 in the afternoon on a winter night when it goes below freezing it will be low single digits in the morning.

[Borris-Bear]

There would definitely be some electric heating in it and not expecting it to be house levels of insulation but useable.

I guess the decision is whether to buy something like the above that has insulated walls, floor and ceiling or whether something without insulations and a DIY insulation after its built.

[Equus]

If you do a search on here, you'll find that it's been discussed many, many times before, but the bottom line is that these 'log cabin' type of structures are not easy to insulate properly, because to do so you need an externally ventilated gap between the timber planks and the insulation.

If you're looking for an insulated 'garden office', I'd look at one of the many SIPs-based options, personally.

[Diderot]

Equus said:

If you do a search on here, you'll find that it's been discussed many, many times before, but the bottom line is that these 'log cabin' type of structures are not easy to insulate properly, because to do so you need an externally ventilated gap between the timber planks and the insulation.

If you're looking for an insulated 'garden office', I'd look at one of the many SIPs-based options, personally.

What he said.

Many, many moons ago (19 years ago) I put a Scandi log cabin up in our then garden - decent thickness wood (can’t remember exactly but I didn’t scrimp on it) and loads of insulation in the floor between the concrete base and the joists. It was ok, did us until we moved, but needed maintenance, the windows were the weakest link IIRC, and having my computers in there always made me a bit jittery.

In our then new house (2006), I got a company in to erect a prefabbed garden studio - 2007 it was. It was brilliant. I had air con in there (inverter) so constant temp, and I know it’s still standing from the current owner and used for its original purpose all these years later. They do last.

When we moved to our new house 4 years ago, I was seriously lucky as there was a brick outbuilding I could convert, but Mrs Diderot has recently had the same company as the 2007 install come back in and build her a new studio. No concrete base required, goes up in 2 days, air con and electrics all pre-wired. Not cheap, (£30k ish for a decent sized one) but I’d have one of those every day of the week over a log cabin unless it was just a summer house type of structure you wanted. I like the aesthetic of the log cabins - very attractive over SIPS type designs.

Edited by Diderot on Tuesday 10th October 19:24

[Aluminati]

This was all oak built in 2012 with 100mm pir which has worked very well. ( Now sold)

Nominal heating from GSHP which also heated the pool.

[Techno9000]

Borris-Bear said:

We're looking to install an insulated log cabin in the garden and were looking at the Dunster House range ...

They claim their 62mm logs with 30mm polyisocyanurate insulation is the equivalent 0f 140mm logs with a u value of 0.57 W/m2K. Is this good?

Does anyone have experience of these products and can verify that they are useable all year round?

I erected a Lugarde cabin with just 28mm thick walls and only put 50mm insulation under the floor, on the roof and inside two of four walls, leaving the walls with the (double glazed) windows uninsulated.

This has done us well over the last seven years or so. Only use it intermittently, but it warms up from ambient with a 2kW fan heater in a few minutes and then a panel heater takes over to maintain a comfortable temperature without the noise.

Wouldn't know what my walls with the 50mm insulation would measure up to in terms of W/m2 but, as a indication, in the 80's I was taught at tech' college that a typical brick - cavity - block wall had a U-value of 1 W/m2, so your U-value (0.57) looks fine for something in intermittent use. At the end of the day it will be easy enough to heat, just a bit more costly than something that is made to current housing spec (0.18).