I am purchasing a Display Model Modular home. During installation what upgrades/additions would I be wise to have performed.
1. In the crawlspace: Should I have a 2″ layer of concrete poured over foam board to improve access and vapor sealing?
2. Floor insulation: Stick with the R-22 Batts of call in a spry foam installer?
3. HVAC System: Fresh Air Recovery system? Round or rectangular duct? How many returns are optimum? Is it money well spent?
Replies
bump
I'm just sayin'
NO FLEX DUCT! Round/Square ... round is best, I think (more efficient), but can take up more space. With a modular house, I suspect there should be little or no excuse for the 'need' for any flex duct at all. The design should have it nailed down. Also, put balance dampers in the major trunks if not at every branch (accessible of course). Rigid ducts ... money well spent. NEVER listen to anyone that claims that flex ducts are 'no big deal'; that is an old wives tale (even a new wives tale). This includes the exhaust ducts.
Do you have options for central exhaust serving e.g. several rooms? I like them ... quiet and efficient (at getting the job done). A number of options for good systems here.
Where are the ducts ... in unconditioned spaces?
Also ... SEAL the ductwork w/ duct sealing mastic ... NO GREY DUCT TAPE!!! Duct tape ... great for EVERYTHING ... EXCEPT ductwork.
I don't think I would bother w/ 2" insulation on the ground ... consider a 6 mil vapor retarder, though. Think the insulation would be somewhat detrimental (unless I'm missing something w/ your description here). Not sure if I would bother w/ expense of only 2 inches of concrete poured on the ground (or even the insulation). Maybe other posters will address this more.
What is your location? R-22 floor in some climates may be minimal ... may not meet code. Are R-30 batts out of the question? What is the perimeter of your crawl? Maybe add insulation there. How is your plumbing protected through the crawl?
That's some two cents from my experience and knowledge. Maybe others will jump in to help add some more perspective. You can see my strong feelings about the HVAC stuff, though; I'm confident that is good advice (and it shouldn't cost you much).
Clewless1:
I plan on Rigid Duct; however right now my estimates the HVAC contractors have sent include a 5'-6' run of flex on each branch for "noise control" ; I feel a properly designed and installed system should be constructed with a Flexible Duct Connector on the main trunk at the air handler, instead of the quick, cheap "fix" of a section of flexible duct. One estimate is for 5 return ducts, the other is for 2. No mention of transfer ducts or grillsLooking at making the crawl space a conditioned space, see post aboveI agree on sealing the ducts with mastic, I did that myself on y previous houseThanks
John
My personal opinion is that crawlspaces should be treated as short basements and the air should be conditioned. That would move the insulation from the floor joists to the crawlspace walls. At the very least you need a vapor barrier on the dirt, sealed to the foundation. In my own house, I would have preferred a concrete floor over insulation versus dirt.
I have seen one modular house with a concrete floor that used the crawlsace as the return, i.e., no return ducts. But I would think to do that, you would need to pay attention to the details so that you were not circulating bad air through your house. Think about radon and water infiltration.
You should add your location to your profile.
Aaron, thanks for the reply.I am located in Aiken SC, between Augusta Ga and Columbia SC.My research agrees with your post. The article Conditioned Crawl Space, Construction, Performance and Codes by Building Science Corporation http://www.buildingscience.com/resources/homeowner_resources/atct_topic_view?b_start:int=20
supports the construction of the crawlspace in that manner.Now to solve the HVAC issues: Condition Air in the Humid South offers a good discussion of this.Now I need to discuss/price the various options with HVAC Contractors to get more detailed estimates.The quest continues, even though I am driving the wife nuts
I've noticed considerable misuse of terms in Colorado. Modular and manufactured housing seems to be mixed. Manufactured is what people now call a trailer--single, doublewide, triplewide. Modular is built within a building and is assembled like blocks on the building site.A contractor is going to install water, gas, sewer and phone lines, excavation, the foundation (may be full concrete basement w/spread footings or crawlspace on spread footings) Engage a crane to move the "blocks", tie in drywall, texture, some exterior prep for landscaping, driveway, roofing, etc. Are you sure what you are getting? Tyr
TVR,Yes I am sure what I am getting.
OFF-Frame Modular built to IBC code NOT HUD.House is 3 modules with a 9/12 pitch roof. Thanks
John
windows & roofing, maybe siding..... depending on their options
most of the interior stuff is window dressing......maybe upgrade the kit. cabinets
I would upgrade to the foam insul. Your home will be more comfortable, quieter, you can get a tax rebate, and down size your HVAC system.
You can always upgrade appliances, counter tops later. Insulation is a one time thing.
http://www.energystar.gov/index.cfm?c=products.pr_tax_credits#s6
http://www.dsireusa.org/index.cfm?EE=1&RE=1
It appears that you are in Climate Zone 6. Minimum floor insulation would be R-19 but remember that is minimum. I'm in zone 13 and that is now R-21. It was zero when the house was built (over full basement). I think you got good advice on HVAC, conditioned crawl, etc. prior to this post. Wall insulation is difficult to upgrade but my guess is your demo unit already has that.
I went to Iowa to observe a modular factory and considered it for myself (pre broken leg). Had a tough time getting price info out of the factories. They always wanted to go through a GC. Showed them my GC license but they still hung back. What did you have to give for a demo unit? Any transport included (usually X number of miles). Never heard of concrete over poly-iso in the Rockies. Tyr
I think you wanted to send that to banzaitoyota.
Yeah you're right. There are times when I have gone back to the original post and other times when I just reply to the last poster in a thread. It ends up in the same place, visible to all, and the only difference is the post heading of "from" and "to". I just had a lap top and scrolling with the touchpad is a pain. So I got lazy. Sorry.
Tyr
Edited 10/22/2008 11:51 pm by Tyr