Vent for Gable House

[dalucca2003]

I am very close to finishing the walls and putting on the roof of my gable house. I plan on filling all the empty spaces with vermiculite, but was wondering if there is a need to install a vent. I have not seen it mentioned in any other thread and cannot see the reason for one.

[dmun]

Re: Vent for Gable House

I put a vent above the vermiculite layer of my insulation. They make vents that are the size of a single brick, that's what I used. I figured that atmospheric moisture that accumulated in my insulation when the oven was cold could use a place to vent off. Also, my superstructure is wood, and condensation on wood is a no-no. That's why your house attic is vented, top and bottom, outside the insulation, to keep the rafters from rotting.

[dalucca2003]

Re: Vent for Gable House

Thanks for the quick reply Dmun.....There is no wood products on the structure so far, but not sure about the roof. I virtually have no heat loss from the oven, so I was thinking of utilizing plywood for the roof and then lay down the clay tile. Or, I could lay down the cement board like the walls, but I thought I read in a thread that screwing down the strips to lay down the tile is more difficult with the cement board. Not sure why, so I am open to any suggestions.

So back to the vent question...sounds like if I lay down plywood, would be smart to vent. If I lay down the cement board, do you still think necessary to vent? There would be no wood products whatsoever.

[dmun]

Re: Vent for Gable House

Aren't tile roofs laid on furring strips or laths? Why do you need plywood?

Also most tile roofs that I've seen are far from airtight: They just serve to channel water off the roof.

[dalucca2003]

Re: Vent for Gable House

I am thinking plywood or some kind of board needs to be layed down so the furring strips can be attached? Kind of like a regular house, at least here in my area. So the other question I had is whether or not the furring strips can be screwed and provide the proper support on the cement board?

If I do go with the plywood, I was going to lay down the black paper in order to provide an additional barrier.

[wlively]

Re: Vent for Gable House

If your oven dome is well insulated, blanket plus loose insulation there is no reason you can't go with plywood on the roof.

I used two pieces of tech shield decking (osb with foil on one side) and then roofing felt and cat 1 high end fiberglass shingles. I had to due to HOA restrictions that it match the house.

[dalucca2003]

Re: Vent for Gable House

Wade,

Did you install a vent or some sort?

[wlively]

Re: Vent for Gable House

Was going to put in ridge vent but decided not too. First, I finished curing my oven before I put the roof on. Second I was thinking as a back-up measure to a dome breach that I did not want the capability of alot of air getting in. I cannot forsee how a dome breach would happen much less penetrate the layer of blanket and foil, but the pilot in me always looks for worse case senarios and back-ups. So, I have a small 2 inch x 1/2 inch gap or opening at the intersection of roof and rear gable, under the eave to be out of the elements. Then stuffed with copper wool to kepp out the bugs.

I know this is not code, but this is also not a house. A house where the lower end is refrigerated and alot of air exchange (windos/doors opening). The only wood is the roof deck and I live in Texas where the temp extremes are not that very extreme. So this may or not be the correct thing to do, but I could not think of a reason to do it different. I also made an acess panel in the middle of one sheet so I can remove a few shingles and inspect if ever the need arises.

[dalucca2003]

Re: Vent for Gable House

Thanks Wade for the great input. First question....what is the difference between tech shield decking and plywood. Also, how thick is the decking material you used?

I basically have the same thoughts as you do; the only difference is in No. California we do get a wider range of temperature changes. We go from 110 in the Summer to low 20's in the Winter. I just might install a small vent in the back of the house and be done with it. It cannot hurt either way as my oven like yours is fully cured and I am not losing any heat. This past Saturday I checked the outside temperature of the left wall of the oven and it was roughly 78 degrees. I pushed the fire to the left side of the oven and when I checked the outside wall again it was 80 degrees and actually dropped later and it got cooler.

I will be filling the entire empty space with vermiculite once I am done framing the vent and walls and I cannot see any issues whatsoever with using plywood under the tiles. I also will utiize felt.

[wlively]

Re: Vent for Gable House

Tech shield is OSB (Oriented Strand Board), the random chip looking wood sheeting, with aluminum foil on one side to reflect IR. It is made specifically for roof decking to lower attic temps. I used it to reflect any heat inside away from the decking and as an extra barrier for the wood, since we are not concerned about solar heating.

OSB is about 2 times stronger in shear than plywood. But either will do for a roof.

[dalucca2003]

Re: Vent for Gable House

I have seen this product at Home Depot, but only in a 3/4" size which I am afraid would be too heavy. If they do not make a thinner product, I think I will be okay with regular plywood.

[tsquared]

Re: Vent for Gable House

Tech shield is OSB (Oriented Strand Board), the random chip looking wood sheeting, with aluminum foil on one side to reflect IR. It is made specifically for roof decking to lower attic temps. I used it to reflect any heat inside away from the decking and as an extra barrier for the wood, since we are not concerned about solar heating.

OSB is about 2 times stronger in shear than plywood. But either will do for a roof.

Did you install a vent or some sort?

[wlively]

Re: Vent for Gable House

Did you install a vent or some sort?

Not really, though there is a small air gap. From earlier post;

Was going to put in ridge vent but decided not too. First, I finished curing my oven before I put the roof on. Second I was thinking as a back-up measure to a dome breach that I did not want the capability of alot of air getting in. I cannot forsee how a dome breach would happen much less penetrate the layer of blanket and foil, but the pilot in me always looks for worse case senarios and back-ups. So, I have a small 2 inch x 1/2 inch gap or opening at the intersection of roof and rear gable, under the eave to be out of the elements. Then stuffed with copper wool to kepp out the bugs.

[dalucca2003]

Re: Vent for Gable House

I ended up installing a small (4") round vent in the back of the gable house. I installed it near the top of the peak which is not visible at all. I did it as a "just in case" but probably did not need it.

[christo]

Re: Vent for Gable House

I bought them and have not installed them.

I burned my oven with the blanket on quite a few times before final close in. I'm thinking if you build the enclosure around the oven before fully cured the vent is a good idea - no sense in keeping all that moisture inside the enclosure. I think I need to drill some holes this weekend.

Thanks