Condensation Problem with Vinyl Roof Cover

[wheesht]

Hi folks,

this is my first post so thanks for reading it...

I live in a yurt imported from Mongolia to England. Where we live it rains a fair amount of the time.

The problem we have is condensation forming directly under the Vinyl cover. We don't have Reflectix-type

insulation

but felt and extra carpet underlay which contains felt and some man-made elements.

The yurt has a Vinyl roof cover which is quite rare round here, most people going for full felt and canvas covers.

The wall consists of felt and canvas (no vinyl).

We cook inside the yurt on butane gas so there are considerable water vapours formed there.

I have seen

Pacific Yurts

for example using Vinyl covers and reflectix-type

insulation

. I would like to do the same and wonder how to go about it.

Do I just put the reflectix insulation directly onto the outside of trellis/roof poles and then the vinyl cover onto that?

Can I keep/Will I still need the felt insulation for extra cosiness or will it still affect the dewpoint and still cause condendsation? It gets down to about 14 Farenheit in winter here, the yurt is heated with a woodburner.

Can I replace the canvas wall cover with Vinyl too? The canvas is rotting on the north side and although i've tried scrubbing and waterproofing, it keeps coming back.

Will Reflectix as a non-breathable insulation make condensation form inside the yurt?

Can I keep the thin white cotton cover as the very inside layer (but still outside the trellis and poles) as it looks better than foil?

I think that's all for now. I'd be very grateful if anyone's read this far to hear your thoughts and suggestions

Many thanks

[Jafo]

Wheest.

Welcome aboard! I hope I can answer at least some of your questions. I have a Pacific Yurt with the reflective insulation and have no real condensation issues myself, but it hasn't been all that wet here since I put it up.

The reflective insulation should not cause any more condensation because it does not act as an air barrier, rather an energy barrier. On my yurt, it goes between the outside lining and the wooden framework.

Do you have an acrylic

dome

where you can let air/moisture out of the ceiling? The reason I ask is that you can ventilate quite a bit of

moisture

out this way. In fact, I am doing that today at my yurt camp. While it is cold and dry, I fire up the wood stove so it is really hot, then open the

dome

and cook the

moisture

out.

Another member had some mold issues, you may find some nuggets of info in her thread about it:

http://www.yurtforum.com/forums/yurt.../mold-184.html

I am up at my camp now and barely have internet service, but when I get back tomorrow I can help more.

[wheesht]

Dear Jafo

Thanks for your speedy reply.

That's good to know about the air/energy barrier. It will be great to get rid of the condensation

we have a 5' diameter hole in the middle of the roof with a roof cap with clear vinyl panels as skylight windows. We have the cap propped open a few inches 24/7 on both sides since discovering the condensation to attempt to allow air to flow - I think that has been helping it.

I've also fitted a 4" extractor fan above the cooker today which will hopefully help too.

It's a good idea to fire up the burner and get the roof cap off - it's hardly on all summer but I don't really think to get it off in the winter - it's held down with tyres at the moment since there were supposed to be gale force winds last night.

I plan to change to reflective insulation , sounds like a good solution - it's far cheaper than changing the vinyl to canvas too.

Many thanks again...hope you get some rain this season at least!

Calum

[wheesht]

Dear Jafo

One other thing - roughly what thickness is your insulation?

Is it foil covered on both sides?

many thanks

Calum

[Jafo]

It is about as thick as small bubble wrap coated in tinfoil if that makes sense?

[wheesht]

That makes sense indeed. Thank you.

[Pacific Yurts]

The reflective insulation used is 5/16" of an inch thick and does indeed have foil on both sides. As long as your felt is dry you could continue to use it, but I would install your liner fabric (preferably not cotton) on the outside of your wood frame, followed by the Reflectix layer and then the felt and your exterior covers. As Jafo mentioned,

heating

the yurt an venting moisture regularly will also help to eliminate moisture build-up, which leads to condensation.

[wheesht]

Great, thank you very much

Pacific Yurts

for the useful information.

What fabric would you make the liner from? My one is of cotton.

Many thanks

Calum

[Pacific Yurts]

If the yurt will be set up for long term use you should stay away from fabrics that are susceptible to mold/mildew, are washable and are resistant to fire. We have used a woven polyester fabric for the liner material for 25 years and it has worked well.

[wheesht]

OK That's great, thank you very much!