Insulation/plumbing questions

[Pafrmboy]

Hi everybody....I'm glad to be part of this group!! Thanks to the moderators that helped me with the registration.

I recently bought a 79 14 X 70 back in my home state of Pennsylvania. The home is a shingled roof and lap siding, skirted and about 3 feet above ground overall. I consider it to be a higher end home for the period. (Coachman)

The home is in super condition, EXCEPT it has been neglected on the underside and it's insulation is....well in BAD need of replacement!!

The home is 2 X 6 on 16" centers. The home is also 1 bath and the good thing is that all the water piping is contained within about 15-17 feet of the total home length.

My plan is to remove most if not all of the non-serviceable insulation.

1. Remove all insulation and clean up the underside, inspect waste lines, telephone and cable lines and ducts.

2. I plan on "relocating" all of the water supply lines ABOVE the floor with PEX. I have the ability to easily hide these lines in cabinets, as all the plumbing is so close together and with lot's of hiding options. I will be adding numerous shut offs and also adding a main shutoff at the point of water entry into the home. (Right at the floor above the MAIN water line underneath). I want easy access to the water lines. I also want to insulate between the floor rafters and not do the big "drape" of hanging insulation. The home is a secondary residence and I will be coming to the home on and off about once a month. The home will need to be able to be rapidly winterized each month after leaving in the winter.

3. I plan to install faced r19 insulation with facing toward floor and support with wire hangers. I then plan to cover the insulation with some sort of material. That is the question. I plan to cover and secure the insulation from the side of home to the 1st I beam, in between the I beams and then the other side of home. Do this front to back. What I don't what to do is use the wrong material to cover and create a moisture problem. I have thought of TYVEK, black woven poly sheeting, or even mesh. Does this covering have to breath? Should I install a NON faced insulation? What's best?

4. I then plan to separately insulate the heating ducts. They will be hanging below the insulated rafters. I thought of just using flex insulated ducts and tearing out the tin ducts. Securing the flex up tight to the rafters, but now lean toward just insulating the tin ducting in some form or fashion. Any idea??

5. Also....can I blow additional roof insulation onto the roof rafters? I have easy access from the front and rear gable vents. I can see right to the rear of the home when looking in! There is currently about 6 " of insulation over the ceiling rafters. There are no soffit vents, just the gable vents front AND REAR that are 1' X 1'.

Am I way off base here, or do I have a pretty workable plan?

I thank you in advance!!! I'm sure I will have more questions, Thanks for the great forum!!

Todd

[Greg]

Hi & welcome.
You will want to get the insulation cleaned up and check everything as long as you are there. I will also bet that there have been critters in there as well so expect that also.

If you can relocate the water above floor fine, but if you are going to winterize it when you leave I would question if it is worth it. You can never have too many shut offs, but buy good ones! I prefer the brass or stainless ball (1/4 turn) valves or brass gate valves. stay away from plastic body valves or the basic "stop" type valves, they fail when you need them the most.

As far as insulation, you may want to think about insulating the skirting as well. Mark is in S.Dakota and claims that the temperature under his home never drops below freezing.

If you have access above the ceiling extra insulation won't hurt, just make sure you also have ventilation.

Greg

[JD]

Hi Todd and welcome to the forum.

You are kind of on your own with the plumbing. When you pioneer new grounds, there is always risk. But I certainly can see how it could work provided you can keep the water lines from the utility supply to the first service, usually the water heater, insulated and free from freeze concerns. Manufacturers will run the lines next to the heat ducts to ensure they don't freeze. In an empty unheated house, I guess they rely solely on insulation. Greg may have better answers for this as I do not live in a freeze area.

The belly in the underbelly as well as the void in the attic is used for air circulation. Again, redesigning the way the home works could lead to unexpected problems. Filling the void with insulation may not give you the benefits you are thinking. Insulation is, for the most part, only as good as it's consistent depth or R-value. Having one area heavily insulated while another is not only moves the warm or cold air to the less insulated space. It may have some benefit, but not nearly the 10-12" that you are thinking. The next factor is the loss of air flow to reduce moisture in the attic area.

The material to use for underbelly is available and well priced through this web site. The actual material used by most manufacturers is in the Books and Parts link at the top of this page. http://www.mobilehomerepair.com/Order2.html#catalog There you will also find Sta-put spray adhesive, which I recommend for the installation. There are many threads on how to install the material to your home with many varied techniques and preferred products to hold it all together. Personally, I would not use faced insulation or wire to hold it up. A T-50 stapler, staple hammer, or pneumatic will hold it in place while setting the underbelly. Doubling up on a vapor retarder is not a big issue in my area as we have a very dry climate and again, no freeze issues to speak of. In colder climates, this could create a moisture problem. The underbelly being bowed is also something to think about, but in my area they do make a lot of homes with the underbelly attached direct to the bottom of the floor joist.

[Pafrmboy]

Thanks for the feedback.

Yes, this home is in north central PA, so it does get cold. It was 8 below when I was winterizing 2 weeks ago! brrrr

I will think about insulating the skirting too!!

I want to bring the water up above the floor, mainly because if I insulate between the floor joists, there will be little free circulating air to keep those pipes warm when I'm there in the winter. (vs the draped blanket).

With the little plumbing this home has, it's just easier to assess and also to keep critters from chewing it.

With the floor insulation having a vapor barrier, maybe I should use a more breathable mesh on the bottom, vs something air tight? Or should I use a non-faced insulation batt and then use a more airtight bottom material, such as http://www.mobilehomerepair.com/Order2.html#catalog
Is the material that is sold on this site like a polyethylene woven mesh? Waterproof? What is the denier weight of this? These are the wires I was planning to use in the floor. http://www.lowes.com/pd_12336-41075-716 ... facetInfo=

As for the water. The main line from the "crock to the water heater" is insulated and heat taped. The MAIN valve in the crock has a bleed cap, so if I want, I can turn off in the crock and empty the main line too. But I would still need a heat tape for the above ground portion of the main line in the crock below the valve. So when winterizing, I will just shut off the water at the trailer, below the water heater, where the main comes in. Leave the MAIN crock water valve open and leave a heat tape on that portion from down in the crock to the trailer/water heater. (and blow the lines out in the home)

Yes, only quality valves will be used with the PEX. The main shutoff at the water heater will be a ball valve.

The roof has plenty of height from the peak to the ceiling rafters. I could add a couple/few inches and still have pretty good breathing room.

I also want to cover the ground under the home with plastic, front to back.

Thanks! Todd

[Pafrmboy]

Any ideas on the heater ducts and how I should insulate? What about tearing out and just using flex. I worry about the vulnerability of hanging flex duct under the home. It would be below the insulation blanket.

Should I just insulate the 2 sides and bottom of the existing duct and call it a day?

Todd

[1987Commodore]

I'd wonder about critters chewing through the flex duct. At least the current metal duct is resistant to that.
If you have only the vents in each gable end, that is not enough. I hope there are some vents through the roof also to provide proper circulation in the "attic." If it were me, I'd enlarge the gable vents also.

[DaleM]

We use the encapsulated insulation for underside replacement/repairs. It breaths and you can pull the plastic to allow for stapling it up. As for going over or under the duct, You may find it easier to calculate to length of the insulation needed to go from one side of the home to the other, add about a foot to allow for the drape under the duct then tuck both ends up over the I-beam, pull the to edge of the home and staple it in. It goes along pretty quick with 2 guys. The belly wrap that works best is the woven plastic sheet. You can cover some pretty big areas easily and quickly with it. We use a small pneumatic stapler to install that. There is a fair amount of heat lost on these duct systems due to ill fitting drops and flex ducting, better off keeping it in the belly of the home.

[1987Commodore]

A good point. Seal the duct seams while you have access.

[JD]

Encapsulated insulation is great stuff. Less itchy and everything Dale said. I don't know the denier weight of the black poly underbelly, but it is strong enough to do anything you would ask of it. Stronger than HomeWrap by a long ways. On rim joist edges, I like to fold a 1" strip of 1/4" ply or used paneling into the edge when I staple it. I use a big 16ga pneumatic stapler, but need to hold it at an angle so it does not blow through the belly wrap. Sealing existing aluminum ductwork is an excellent suggestion and much easier to do than any kind of replacement. The flex won't stand a chance against critters and will collect a lot more dust. If i were to replace it, I would go with new metal ductwork.

[Pafrmboy]

Thanks all....I appreciate all the good information. I will keep you posted on the progress after the weather breaks.

BTW.....what would be a reasonable labor charge to remove and install insulation, bottom cover and haul away the trash?

Also, to re-plumb this 1 bath home. (With PEX) Bath and kitchen are back to back in the home.

(Myself providing all materials for both jobs)

[Pafrmboy]

Insulation again!

Would it be best to put "unfaced"/no vapor barrier R19 in the floor of this home or "faced"?

The reason I ask is that if you put the bottom board/poly material on the bottom, you now have essentially (2) vapor barriers. The paper against the floor and the poly bottom. Maybe have the paper facing face down, vs against floor? That way the 2 vapor barriers would be against each other.
I'm not at the home now, but I think the original insulation in the floor was "unfaced".

Thanks

[Greg S]

Vapour barrier goes on the warm side of the insulation (heated side) otherwise you end up with a sponge with no insulation value.
The belly material should breath allowing moisture to escape.

[Greg]

Thanks all....I appreciate all the good information. I will keep you posted on the progress after the weather breaks.

BTW.....what would be a reasonable labor charge to remove and install insulation, bottom cover and haul away the trash?

Also, to re-plumb this 1 bath home. (With PEX) Bath and kitchen are back to back in the home.

(Myself providing all materials for both jobs)

Labor prices vary depending on your area, I would figure about 3 days of work minimum (JD may have a better estimate) to start with.

Greg

[Pafrmboy]

Yea....don't want a soaked sponge!!


I'm confused...I thought that the belly wrap was supposed to be airtight, so that would mean not breathable. What is the best bottom material that IS breathable? I'm thinking it may be best to add unfaced and then then use the belly material as a the vapor barrier, but the belly paper/poly/whatever, is not toward the heated side.

So my options:

1. Unfaced insulation between the 2 X 6s. held up with spring wires and a poly type bottom material.
2. Faced insulation between the 2 X 6s. (facing against floor), held up with spring wires and some type of "breathable" type bottom material.

Todd

[DaleM]

You're overthinking this stuff. Using the encapsulated gives you a product that breathes, is easy to handle and staple up. Cutting it full length allows one to push each end over the I-beam and the center of it under the duct work creating the belly or sag between the beams where all the plumbing is located. There is minimal work in this method as it damn near hold itself in place. Usually there is about 3'-4' of home on each side of the I-beam which provides much of the holding action on the insulation when it's tucked in between the floor joists.

Best bottom material is the woven black plastic/nylon stuff. Virtually indestructible. You can pull it real tight and any holes or seams can be made very well with small pieces of the product and spray adhesive.

Most repairs we do are just sectional and rarely an entire unit. However we did do a doublewide last year. The home was in a flood and had 2" of water in the insulation. The homeowner was proactive and cut down all the insulation and ductwork, all of it was trashed. After the slab and home dried out we installed new main ducting custom made for the home, new flex duct to all his register boots, all new insulation, 6" encapsulated, all new belly wrap, the black woven type estimate on that job was $10,500. That homeowner wanted to help so we worked with him and he busted his butt for 4 days with us. When the job was done we knocked off $1000 to cover his part of the labor. I would say if we cut it down and hauled it away I would have added another $3000. He told us he was 3 days cutting it all down and hauling it to the dumpsters the park had provided the victims in the flood. I guess a safe figure would be $6000 for a reinsulation job on a single wide home, start to finish with no duct work involved.