Builder opinions needed

jasonmotox · 10-15-2008, 08:19 AM

I happen to be building a 4 million dollar house (not for myself) on the Atlantic coast. The problem is I'm having a differance of opinion with the architect, I'm the project manager. Although I'd like to post a pic, I think I would be betraying the clients privacy soo... I'll try to explain it.

The house consist of a stone tower 3 stories tall plus a below grade garage.
Ajoining the tower at the second floor is a 3200 sqft "wing". The walls on the wing lean out at the 107 degre angle (all the wall around the wing) There's not a square corner in the whole house (maybe one?). The siding on the house (leaning exterior walls and the underside of the wing) is T&G cypress.
Got the picture??

The problem lies in that the architect wants me to put vents in the soffit (underside of wing). They came up with this after they visited the site last week and now they are dead set on it. They are worried about moisture being trapped in the soffit and thus causing the bottom of the house to rot from the inside out.

My stand on this (and I think I'm bit more qualified because I know the construction of this house, been here over 2 years) is that since we will be putting a moisture barrier over the sheathing before the siding goes on that no moisture should make it into the soffit much less get trapped.
Also 2 things to note is we sprayed open cell foam up into the floor trusses (above the soffit space) and the main structure is steel and we were never instructed to add any additional rust proofing to th beams. We have a red oxide primer, but I don't think letting moisture up through the vents is gonna help them. If we make the "box" airtight then the temp and humidity should be minimum. Remember its under the house floor so its not gonna get any sun or rain.

So 2 questions.... to vent or not to vent......to moisture barrier or vapor barrier (plastic or tyvec?)

Sorry if this is a boring thread, I'm just curious to see what others think. Maybe somebody with knowledge in humidity, condensation, or insulation
could help?

Thanks for the help,

**DeadRiver** · 10-15-2008, 09:19 AM

I believe the architects concern is that the moisture that is generated within the house will create the moisture as in Florida you use a ton of cooling. Cooling creates moisture as you know. A home needs to breath believe it or not.... Some air does have to come in and escape.

I don't have a good visual of the project but it would seem that the "wing" cantilevers out from the lower portion.

Bottom line is that the Architect is the design professional. His seal is on the project, he's liable for it. If he says to put vents in, put them in. It's no hair off your *** now or later...... his call. Write him a nice fat change order and call it a day.

Take a look at my profession, you'll get a chuckle.

*looking* · 10-15-2008, 09:19 AM

If you used sprayed foam cell insulation there should be no need for the vents as there should be no significant temperature swing with the insulation..

The only reason you would have a moisture problem is if you had an envelope problem, or if there was a swimming pool or hot tub in the room or outside the wall.

Otherwise the vent would allow for more moisture too infiltration.

An if your Red Iron only has prime coat I would also be concerned about rusting on the coast. Need at least 2 coats of paint or galvalume.

I would go with at least a 4-6mil visqueen for your moisture barrier. An if
there is a need for it use a good mastic peel and stick, it would be best.

My 2cents

Frank

SpiritOne · 10-15-2008, 09:29 AM

Quote:

Originally Posted by jasonmotox

I happen to be building a 4 million dollar house on the Atlantic coast.

does it matter? Hurricanes will most likely destroy it before mold does.

sorry, I know nothing about building.

bestatchess · 10-15-2008, 10:37 AM

My understanding is that open cell foam is not a moisture barrier, so the concern would be that humid air from the house would get into the soffit and then water vapor would condense in the cooler soffit space. I was involved in a mold battle concerning a California beach house and they ended up having to install a dehumidification system to control the mold. You might consider talking (or preferably writing) the owner about the issue and suggesting they pay for consultation with a construction expert regarding the soffit venting or non-venting and the possibility of steel rust. That way if there are problems later, you have CYA.

Architects are frequently wrong and depending on local laws they may be protected against liability by time limits. I was involved in a $20 million commercial construction project and the architect missed the boat numerous times. The super ended up re-designing alot of the building on the fly in consultation with the owner. I sat in on a couple of the meetings and it was extremely embarrasing for the architect. It ended up being almost "Here, dummy - stamp this." The funny part is that the architect ended up getting a design award from the local county government for the building. I am all for double-checking the architect's work.

grnTitan04 · 10-15-2008, 11:22 AM

I agree with BAC. Remember that many architects start out as art students, not engineers.

OTOH - If it ain't yur azz...

*looking* · 10-15-2008, 12:40 PM

I would think with a house that big it would have some sort of system reheat or dehumidification system.

Is there any sort of clear story that would cause that particular area to heat and cool substantially to create the moisture?

**DeadRiver** · 10-15-2008, 12:43 PM

I'd like to see a picture.

It's not like you're giving out personal information.

The person responsible for double checking everyones work (architect and contractor) is the building plans examiner, as well as the building inspector.

**konigfritz** · 10-15-2008, 01:17 PM

Jason from my experience in fixing moisture problems. Cedar siding with a tyvek type wrap and closed cell foam or fiberglass/blown insulation work well.

check out this out,. Cor-A-Vent : Ventilation Products they have some good "hidden:" venting options. If this house is on the coast or in FL. you will want some good attic/soffit venting of some sort.

**konigfritz** · 10-15-2008, 01:19 PM

I should have asked what type of walls they are.
Standard OSB/Ply or the new green coated OSB...

jasonmotox · 10-15-2008, 02:46 PM

Wow, what a lot of responces! this will take a minute to respond to...

jasonmotox · 10-15-2008, 02:52 PM

Quote:

Originally Posted by DeadRiver

I believe the architects concern is that the moisture that is generated within the house will create the moisture as in Florida you use a ton of cooling. Cooling creates moisture as you know. A home needs to breath believe it or not.... Some air does have to come in and escape.

I don't have a good visual of the project but it would seem that the "wing" cantilevers out from the lower portion.

Bottom line is that the Architect is the design professional. His seal is on the project, he's liable for it. If he says to put vents in, put them in. It's no hair off your *** now or later...... his call. Write him a nice fat change order and call it a day.

Take a look at my profession, you'll get a chuckle.

First off, with the floor joists and subfloor completely covered in spray foam and the top of the subfloor receiving a layer of felt...I don't see how cold air is going to escape into the soffit space below the insulation?

Yeah the architect is going to make the final call, but after so much time invested in the project I'd hate to let them screw up at the cost of the client. As Bestatchess said, they are frequently wrong. They talk as if what they say is fact when they typically have only a general knowledge on the subject. (much less, have they ever physically built anything)

jasonmotox · 10-15-2008, 02:54 PM

[quote=bestatchess; I am all for double-checking the architect's work.[/QUOTE]

Ditto

jasonmotox · 10-15-2008, 02:56 PM

Quote:

Originally Posted by SpiritOne

does it matter? Hurricanes will most likely destroy it before mold does.

sorry, I know nothing about building.

This thing has thousands of yards in concrete and 45 tons of steel. Its somewhat areodynamic and its on the back side of an island off the coast of Georgia. Do I think it could fall....no way.

jasonmotox · 10-15-2008, 02:58 PM

Quote:

Originally Posted by looking

I would think with a house that big it would have some sort of system reheat or dehumidification system.

Is there any sort of clear story that would cause that particular area to heat and cool substantially to create the moisture?

The only thing that could cause moisture in the space would be if there was a leaky ac duct. Hopefully that won't happen. There is a pool but its not directly under the house.