Insulated Concrete Forms

[rpeter]

I have noticed some mention of Insulated Concrete Forms (ICF) in previous threads and was wondering how people liked the construction technique? I am building a one story house with a walkout basement and have been looking at using something like eco-block (www.eco-block.com).

[Pat]

I did a tad over 1000 sq ft in ICF and it has its plusses and minuses but in aggregate I like it especially the thermal characteristics, no infiltration, tornado and nearly bomb proof. I have an "atomic" projector clock with indoor and outdoor temps. The readings are projected on the wall. We go to bed with no heat turned on and an inside temp of say 73F with outside temps falling down to 50 overnight. We wake up with 73F in the room. I was doing manual labor i the room and wanted some A/C. It didn't take much to bring the temp down. The ICF portion of our new house (See Southern Oklahoma Farmhouse thread on this forum) can be heated with a candle and cooled with an ice cube. The vaulted great room changes temps a lot more as the outside temp changes and it responds to solar loads. IT is 2x6 stick construction.

An all ICF house could be terrifically energy efficient.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[egon]

Makes a good heat sink.

Egon [img]/forums/images/icons/grin.gif[/img]

[GaryM]

My foundation was done with ICFs, Arxx, and we are quite happy with the results. In our situation the only "above grade" wall is the East wall of the finished basement. The rest of the basement walls are above grade on the other three sides.

When it ground temp is low, in winter, there is no feeling of coldness on this finished wall. The drywall is the same temp as the room air temp.

I wish I'd had the resources to do the whole house in ICFs up to the roof.

[Pat]

Gary,

" the only "above grade" wall is the East wall of the finished basement. The rest of the basement walls are above grade on the other three sides."

I think you know what you meant and I have a 90% chance of guessing at the 50-50 chance and will probably get it wrong.

Oh, by the way... Does the noise in my head interfere with our communications?

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

That statement doesn't make much sense now that I read it! [img]/forums/images/icons/mad.gif[/img]

I guess what I was trying to impart was that it's the only "full height" wall. All the others are below floor level. Well except for the walls around the saferoom.

[Pat]

Gary, Second verse, same as the first, hoped it would get better but it only got worse!

Now I'm visulaizing a rectangular basement with one full height wall and the others shorter. So is the basement ceiling tilted, three of the basement walls don't reach the floor, or are the walls shorter than the ceiling (subterranean viewing possibillities?)

ICF in the basement offers much less gain over conventional construction than ICF versus stick. I have no insulaltion on my walkout wall but R-11 on the other 3 walls and R-11 under the slab and R-"bunches" in the ceiling (probably high 20's to mid 30's or more.) All my basement insulation is on the outside of the enclosed volume. I used InsulDrain for the walls, PanelDeck for the ceiling, and R-11 rigid foam sheets under the slab. My thermal performance easily rivals that of ICF but at lower cost AND my best available concrete guys were not ICF smart.

I know you know what you have. I believe none of the above are "IT" but from your comments, what you have isn't clear.

I also have a rectangular basement. All my walls are the same height. One of them (South/downhill side) is exposed to air (typical walk-out basement) and the other three are all below grade with dirt against them to nearly the top.

How many of your basement walls are out of sight behind dirt. Three of mine are.

We ran heat/air ducts in the basement but they won't be doing much as it is so easy to heat and cool that the thermostat is turned off most of the time. When the 'stat is enabled the zone control rarely has to activate the basement dampers.

When I get the wainscot done in the basement and carpet glued on the walls, the insulation value of the wall coverings might decouple the thermal massof the 12 inch concrete walls from the room air enough to allow greater temperature excursions which will trip the 'stat more often. The radiant environment will get "livelier" too as the wood and carpet will get warmer faster than the concrete does. The storage capacity of the wall coverings will practically be nil so overall the main change will be runing a little more heat and air.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

Guess you'll just need to hop in your Prius and drive to Warrenton! [img]/forums/images/icons/smile.gif[/img]

Yes, all the basement walls are the same height. [img]/forums/images/icons/grin.gif[/img] The East wall is ICFs, the North, West, and South walls are Structural Insulated Panels (SIPs). The interior walls around the saferoom are also ICFs.

[Pat]

Gary, Be careful what you wish for!

So, your "basement" has one earth sheltered wall and three walls backed by air and daylight.

Sounds like a two story house with one wall of the ground floor earth sheltered.

I too lament the funding restrictions that prevented much more extensive use of ICF. If I were in my 30's instead of 60's It may have made more sense to use significantly more ICF given an additional 30 years to amortize the cost against heating and cooling costs. I probably would have not changed the overall design or looks of the house much, if any, except to accomodate any differences in structural requirements.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[GaryM]

</font><blockquote><font class="small">In reply to:</font><hr />
So, your "basement" has one earth sheltered wall and three walls backed by air and daylight.

Sounds like a two story house with one wall of the ground floor earth sheltered.

[/ QUOTE ]

Yes, that's exactly it. The lower level has windows on three sides. From the East it looks like a one story house, and from the West it looks like a two story.