Author Topic: Floor insulation on a pier and beam floor ...  (Read 6777 times)

0 Members and 1 Guest are viewing this topic.

Offline BobHHowell

  • Junior Member
  • **
  • Posts: 43
  • Gender: Male
Floor insulation on a pier and beam floor ...
« on: October 14, 2012, 07:27:59 AM »
 ???

The last of three boys is out of the house and we need to downsize.  We plan on building a smaller home on some land in NE Ohio not too far from where we currently live.  Being originally from Georgia, we didn't grow up with basements.  While we have enjoyed our basement here, I think every basement on the planet has some problem or another.

So, we want to go pier a beam.  Besides the avoiding basement issues, pier and beam is cheaper ... and you don't have to tear up the land to do it.  But I have some questions.

  • Best Insulation -- While R30 is available in bats, I have seen too many pictures of fiberglass hanging out from under floors to be impressed.  Closed cell seams like the way to go -- if you have a treasure chest of gold to dig up and spend.  Suggestions?
  • Am I Nutz? -- Most of the buildings on this site promote pier and beam -- many in cold climates.  But I will soon be celebrating 30 years of marriage -- and would like to have a few more.  If my wife puts her feet on a cold floor too many times, I will be outside in the dog house.  Do pier and beams mean cold feet?
  • Moisture Problems -- With a little bit of trellis to keep out the skunks and raccoons, I am guessing a pier and beam is still open enough that it will not develop its own climate to create condensation in the summer.  Is this true -- or does a pier and beam create the same issues as a crawl space.
  • NE Ohio Soil -- I think this last question will really require specific information about the building site.  But generally speaking, it seems that the footers do not have to be dug down to bedrock.  I have read about cases in the south where piers are dug very deep to hit bedrock.  When is digging to bedrock a necessity?  When is a good footing enough?

Your thoughts, experience, and opinions are welcome and appreciated.

BHH

Offline PEG688

  • Master Craftsman
  • Journeyman
  • *****
  • Posts: 3,515
  • Whidbey Island , Wa.
Re: Floor insulation on a pier and beam floor ...
« Reply #1 on: October 14, 2012, 08:12:40 AM »
???

  While we have enjoyed our basement here, I think every basement on the planet has some problem or another.

  It doesn't need to have problems , ventilation and a good perimeter drain system can insure a dry useable basement .


So, we want to go pier a beam.  Besides the avoiding basement issues, pier and beam is cheaper ... and you don't have to tear up the land to do it.  But I have some questions.


 Post and pier means a crawl space , so not a basement , but still a space that needs insulated and ventilation.

  • Best Insulation -- While R30 is available in bats, I have seen too many pictures of fiberglass hanging out from under floors to be impressed.  Closed cell seams like the way to go -- if you have a treasure chest of gold to dig up and spend.  Suggestions?

  Again , installed properly batts no not have to hang down or be unsightly. I Ohio yu might go with a flash and batt system , a few inches of spray foam with batts applied after the foam is cured. 



  • Am I Nutz? -- Most of the buildings on this site promote pier and beam -- many in cold climates.  But I will soon be celebrating 30 years of marriage -- and would like to have a few more.  If my wife puts her feet on a cold floor too many times, I will be outside in the dog house.  Do pier and beams mean cold feet?

Most of the building here are considered cabins , BUT even if you go post and beam you'll still have floor joist bays to insulate. I think your confusing pier and beam with a car decking / no floor joist floor system . 


  • Moisture Problems -- With a little bit of trellis to keep out the skunks and raccoons, I am guessing a pier and beam is still open enough that it will not develop its own climate to create condensation in the summer.  Is this true -- or does a pier and beam create the same issues as a crawl space.

 Yes sort of , you are still creating a under floor space , commonly called a crawl space , as to get around under the house you'll be crawling , not standing. So the space needs to be vented and enclosed to keep uninvited guest out.


  • NE Ohio Soil -- I think this last question will really require specific information about the building site.  But generally speaking, it seems that the footers do not have to be dug down to bedrock.  I have read about cases in the south where piers are dug very deep to hit bedrock.  When is digging to bedrock a necessity?  When is a good footing enough?

 NE Ohio , you need to get what ever footings you under under the frost line , or you may be able to use a slab on grade foundation.  Which becomes the sub floor on the ground level. It would need to comply with codes in the local area , be thicked at the edges , and at any bearing points . So it's a different way to build off of than you've been talking about. 




 Welcome to the forum , good luck with you build .  w*
When in doubt , build it stout with something you know about .

Offline BobHHowell

  • Junior Member
  • **
  • Posts: 43
  • Gender: Male
Re: Floor insulation on a pier and beam floor ...
« Reply #2 on: October 14, 2012, 01:44:15 PM »
I am not confusing this with anything.  I am referring to the type of foundation discussed on this site: http://countryplans.com/foundation/index.html

When I am referring to a crawl space, I am referring to a continuous vented or unvented wall like this:


The "best practices" for crawl spaces these days indicate these need to be completely encapsulated and dehumidified (aka conditioned).  I want to avoid that -- depending on the answers I get.

Slabs have an advantage of thermal mass.  But they are extremely expensive to fix if they fracture.  However, a pier & beam or crawlspace are easy and cheap to fix should as they settle.

My questions were related to foundations that look like this:



Offline PEG688

  • Master Craftsman
  • Journeyman
  • *****
  • Posts: 3,515
  • Whidbey Island , Wa.
Re: Floor insulation on a pier and beam floor ...
« Reply #3 on: October 14, 2012, 03:10:24 PM »
 
 Do you want to live in a house in NE Ohio that's open underneath like that?

 I guess I'm not the guy to help you as you have me confused as to what you want answers to.

 G/L PEG
When in doubt , build it stout with something you know about .

Online JRR

  • Senior Member
  • ****
  • Posts: 885
  • 1000', Southeast, USA.
Re: Floor insulation on a pier and beam floor ...
« Reply #4 on: October 14, 2012, 04:55:47 PM »
I have no experience with pier and beam.  But I have seen it used a great deal in Southeastern coastal areas, especially in what seems to be vacation homes.  I guess it takes care of some flooding, but if the big hurricanes come and wipe everything out; it's not so expensive to replace.

What I "THINK" I would do in your area is to use regular decking atop the floor joists, spaced to keep critters at bay but allowing water to flow down and out.... if need be.  On top of the decking I would install high-compression rigid foam, thick enough to take care of all the insulation needs....and on top of that the flooring system .... either plywood and t&g flooring, or wire reinforced mortar and tile.

Like I say, I'm just talking!

Offline Erin

  • Senior Member
  • ****
  • Posts: 549
  • Gender: Female
  • SW Nebraska/NW Kansas
Re: Floor insulation on a pier and beam floor ...
« Reply #5 on: October 14, 2012, 08:18:19 PM »
For right or for wrong, when my dad built his cabin 35 years ago on a pier and beam foundation, he basically made a ceiling under the floor joists (that is, he attached ply to the underside of the floor), then put batt insulation in the joist cavities, then laid the subfloor.
Given newer methods in the decades since, I'm not sure he would have gone this route exactly the same way again.  Perhaps a flash&batt or a layer of polyiso or something...
But it's served them well for over 30 years.  And this is in northern Nebraska, btw.  A bit north of anywhere in Ohio if I'm not mistaken, with the added joy of prairie winds. 

Yes, the floors can be cold.  Had they ever planned to live in it full time, he might have put more effort into preventing that.
But to get around it, you might investigate radiant heat tubes like WarmBoard that aren't buried in a slab.

And to depth, he used a type of sonotube, dug them down below frost depth (standard procedure), and put brackets in the cement before it set up to hold the beams that hold up the house.
The wise woman builds her own house... Proverbs 14:1

Offline PorkChopsMmm

  • Full Member
  • ***
  • Posts: 114
Re: Floor insulation on a pier and beam floor ...
« Reply #6 on: October 15, 2012, 06:04:45 AM »
We built a pier and beam home in Michigan -- zone 5. Was meant to be seasonal and has now turned into a full-time residence. If I could do it again I would do a perimeter wall concrete foundation for the peace of mind. Also, this takes care of 'skirting' the bottom of the cabin. We insulated the floor, installed a vapor barrier, and then installed galvanized hardware mesh to keep critters out of the floor area. It has been working well. That being said, my plan is to still skirt the bottom of the cabin and install foundation vents that we close in the winter and leave open Spring through the Fall. My wife doesn't like cold feet, either, and has no complaints with our current set up. I mainly want to keep critters out.

I would recommend "super-insulating" whatever you build and it will take care of floor temperatures. We only marginally insulated and I wish I would have spent the little bit of more money earlier on and gone with R-30 walls, R-60 roof, etc.


Offline Arky217

  • Full Member
  • ***
  • Posts: 136
  • CountryPlans member
Re: Floor insulation on a pier and beam floor ...
« Reply #7 on: October 15, 2012, 07:20:38 AM »
I am not confusing this with anything.  I am referring to the type of foundation discussed on this site: http://countryplans.com/foundation/index.html

When I am referring to a crawl space, I am referring to a continuous vented or unvented wall like this:


The "best practices" for crawl spaces these days indicate these need to be completely encapsulated and dehumidified (aka conditioned).  I want to avoid that -- depending on the answers I get.

Slabs have an advantage of thermal mass.  But they are extremely expensive to fix if they fracture.  However, a pier & beam or crawlspace are easy and cheap to fix should as they settle.

My questions were related to foundations that look like this:


Something doesn't look right on these two houses.

The posts look like 4x4's sitting on the top of piers and, although it's hard to see with the shadows, there doesn't appear to be any bracing of the posts.

If that's the case, I would be very concerned about the stability of the foundation.

I also built my house on post and pier with the posts sitting atop the piers like these two houses, however, I made sure to brace it thoroughly as shown below.

The posts are 6x6's from the red heart of cedar and the bracing is southern yellow pine; all milled
from native trees on the land.



I'm still working on the house and haven't insulated the floor yet.
The floor joists are 2x8's and I'll be using Roxul batts between the joists, covered by osb.
I'm in Arkansas, so hopefully the floor will be warm enough at R28.

Arky

Offline Erin

  • Senior Member
  • ****
  • Posts: 549
  • Gender: Female
  • SW Nebraska/NW Kansas
Re: Floor insulation on a pier and beam floor ...
« Reply #8 on: October 15, 2012, 08:21:01 AM »
While extra bracing sure doesn't hurt anything, under a certain height (as well as local wind loads), it isn't required.   And the compressive strength of a 4x4 post is pretty substantial, but I would bet those 4x4s are placed closer together than your 6x6s, to make up for the smaller size.
The houses in the pics are probably built to code...
The wise woman builds her own house... Proverbs 14:1

Offline Arky217

  • Full Member
  • ***
  • Posts: 136
  • CountryPlans member
Re: Floor insulation on a pier and beam floor ...
« Reply #9 on: October 15, 2012, 08:55:07 AM »
While extra bracing sure doesn't hurt anything, under a certain height (as well as local wind loads), it isn't required.   And the compressive strength of a 4x4 post is pretty substantial, but I would bet those 4x4s are placed closer together than your 6x6s, to make up for the smaller size.
The houses in the pics are probably built to code...

I wouldn't be so sure about that.
Assuming the side window on the house on the right is 3' wide and using it as a visual aid to determine the spacing of the posts, it would appear that the spacing is around 6'.
Six feet is the spacing of my posts as well.

As far as bracing not being required if the posts are under a certain height, well, for 4x4 posts, I would not be happy about their unbraced stability unless they were no higher than about 6".

But to each their own; I just know that it would be pretty sad if a strong wind caused the posts to topple over. Seems like some bracing would be a real inexpensive and smart way to insure against the possibility of that happening.

Arky

Offline Erin

  • Senior Member
  • ****
  • Posts: 549
  • Gender: Female
  • SW Nebraska/NW Kansas
Re: Floor insulation on a pier and beam floor ...
« Reply #10 on: October 15, 2012, 11:15:13 AM »
Quote
Assuming the side window on the house on the right is 3' wide and using it as a visual aid to determine the spacing of the posts,
I did the exact same thing.   :)
But for me, judging by the post under the corner of the house, just to the right of the window, and the one that's almost directly under the left side of it, I'm seeing more like 4' o.c. 
Quote
I would not be happy about their unbraced stability unless they were no higher than about 6".
And really, that's why engineering tables exist.  So we don't have to go with our gut-feeling on this stuff, either by over OR under building...  Personally, I'd probably have braced the taller porch on the left, but that doesn't mean it would actually be required.

I wish the OP would tell us where these pics come from because these houses look really familiar... And I'm still sticking with my theory that these are built to code and are probably plenty strong enough to withstand Mother Nature in their area.  (Post-Katrina houses, maybe...?)
The wise woman builds her own house... Proverbs 14:1

Offline BobHHowell

  • Junior Member
  • **
  • Posts: 43
  • Gender: Male
Re: Floor insulation on a pier and beam floor ...
« Reply #11 on: October 15, 2012, 03:59:59 PM »
Arky:

If I had a blue ribbon to give you, I would.  That is the nicest pier and beam foundation I have ever seen.  Some fine looking wood and thoughtful construction.  I could see elephants dancing on that foundation without a problem.

Are you planning to add a skirt?  If so, how are you thinking of constructing it?

BHH

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 15,710
  • Gender: Male
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Floor insulation on a pier and beam floor ...
« Reply #12 on: October 15, 2012, 04:10:42 PM »
Quote
The houses in the pics are probably built to code...

Probably not, at least not if the code used was IRC, and the IRC is the most widely used code in the USA.

While 4x4 posts may have the compressive strength to support a lot of structures, they have very low lateral movement resistance. The thing that males a perimeter wall foundation so rigid is twofold. Lots of surface area to bear laterally against the soil and everything is tied together making a rigid box... like having lots and lots of bracing. Piers/posts without bracing is not wise.  But then many people don't give enough thought to wind loading, IMO.

Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline BobHHowell

  • Junior Member
  • **
  • Posts: 43
  • Gender: Male
Re: Floor insulation on a pier and beam floor ...
« Reply #13 on: October 15, 2012, 04:38:34 PM »

Quote
I wish the OP would tell us where these pics come from because these houses look really familiar...

Erin:

These came right off of www.countryplans.com.  (http://www.countryplans.com/leblanc.html)

BHH

Offline Arky217

  • Full Member
  • ***
  • Posts: 136
  • CountryPlans member
Re: Floor insulation on a pier and beam floor ...
« Reply #14 on: October 15, 2012, 06:12:41 PM »
Arky:

If I had a blue ribbon to give you, I would.  That is the nicest pier and beam foundation I have ever seen.  Some fine looking wood and thoughtful construction.  I could see elephants dancing on that foundation without a problem.

Are you planning to add a skirt?  If so, how are you thinking of constructing it?

BHH

Well, thank you sir for the compliment.

(Actually, that foundation as well as the entire house (minus interior walls and the treated lumber for the porches) was constructed from yellow pine and cedar that I milled from trees on the land with a Logosol chainsaw mill)

I'm still working on the house, but here's a picture from not too long ago.
I've since stained the porches and foundation, wall insulation and all drywall done, electrical done, now working on the plumbing.

It's  been a big job for this old guy of 67. It takes a long time when your're working alone. Some stages are really challenging, like putting up the trusses by yourself ( yeah, I made those from the yellow pine as well).

Anyways, I've enjoyed it for the most part, especially making the lumber.

Regards,
Arky



Offline Ndrmyr

  • Full Member
  • ***
  • Posts: 113
  • Gender: Male
  • CountryPlans member
Re: Floor insulation on a pier and beam floor ...
« Reply #15 on: October 16, 2012, 05:02:06 AM »
Peg, as usual, you gave some insightful bullet point responses. IMHO, the reason you see so many pier and beam construction here is because of the demographic of builders you are dealing with.  Many DIYers, much building in remote areas, some off the grid, and in many of those cases, delivered concrete is either pricey, or, impossible.  In addition, excavating for a full basement requires heavy equipment, and bears many of the negatives of the concrete itself.
What most of us northerner's know, is, a basement is usually the cheapest square footage of a house, but, that might not be the case for a cabin.  In my own case, I nearly went with pier and beam, but ending up with a slab incorporated into a seawall.  47 yds of concrete, but it survived a 100 year rain (18" in about 30 hours that flooded others nearby).  If you go slab, you almost forced to consider radiant floor heat, if, the pier and beam, then insulate, insulate, insulate.  Either sprayed or hard foam, or if fiberglass, I would like to see it encapsulated in some way to protect it from moisture and critters.  I've not seen much fiberglass exposed that didn't degrade. Good luck, build to your skill and ability and....location and circumstances.
"A society that rewards based on need creates needy citizens. A society that rewards based on ability creates able one."

Offline Erin

  • Senior Member
  • ****
  • Posts: 549
  • Gender: Female
  • SW Nebraska/NW Kansas
Re: Floor insulation on a pier and beam floor ...
« Reply #16 on: October 16, 2012, 06:59:40 AM »
Erin:

These came right off of www.countryplans.com.  (http://www.countryplans.com/leblanc.html)

BHH
Doh!  I knew they were familiar!!  lol
In which case, they were built from John's plans, and if I'm not mistaken, those include fairly descriptive plans for post and pier foundations.  Though he calls for 6x6, so we might not be seeing what we think we're seeing anyway.

Again, I'm betting the lack of height makes cross bracing redundant.  My point was simply that there's nothing wrong with redundancy (I have multiple redundancies in my house), but not putting such in doesn't automatically mean the foundation will be weak... Or even a cause for concern.
The wise woman builds her own house... Proverbs 14:1

Offline BobHHowell

  • Junior Member
  • **
  • Posts: 43
  • Gender: Male
Re: Floor insulation on a pier and beam floor ...
« Reply #17 on: October 16, 2012, 08:48:25 AM »
Arky:

We're planning on building a shotgun house as well.  While we live in Ohio, we are originally from Georgia.

A shotgun house has a southern appeal.

BHH

Offline Arky217

  • Full Member
  • ***
  • Posts: 136
  • CountryPlans member
Re: Floor insulation on a pier and beam floor ...
« Reply #18 on: October 16, 2012, 09:56:21 AM »
Arky:

We're planning on building a shotgun house as well.  While we live in Ohio, we are originally from Georgia.

A shotgun house has a southern appeal.

BHH

Never heard of the 'shotgun house' description. The house is 24'x48' and the lay of the land is partly why I built it like that with the front at the end of the house. It's length follows the ridge that it is built on and all sides slope away from the house.

But I guess 'shotgun' would be a good description. The front faces SW, the same direction that the power line clearing comes in on, and when both doors are open, I get a good tunnel effect breeze even on the hottest days. I'm going to have to add screen doors to take advantage of that.

Here is the room layout; the door on the right is the front:



Arky