ICF insulation improvement ?

ecomodded · 08-14-17, 06:21 PM

Im preparing to build a passive ICF rancher with a crawl space next year could use some schooled advice on the insulated blocks insulation and condensation.

The blocks use 2 inches of insulation for both the inner and outer wall so the center of the wall is the cold/warm meeting point.

Do they do this to prevent condensation or just ease of manufacture ?

Im thinking (oh no)

I want to add an additional 2 inches of insulation to the outside wall to push the meeting point to the outside of the concrete instead of the inside as designed.

My worry is it will cause condensation to form on the outside of the concrete wall and insulation face causing mildew ?

could use tips or advice what do you think , 4 inches insulation on the outside concrete wall 2 inches on the inside is a good idea or bad ?

oil pan 4 · 08-14-17, 10:25 PM

2 inch foam panels are rated for about R-6.5

I have never seen any complaints about condensation.
I think ICF construction is a great idea.

ecomodded · 08-15-17, 10:46 AM

I was reading that many people use thicker insulation on the outside all the way up to 12 inches thick in some cases.

Not sure why manufactures design these with equal thicknesses of insulation seems counter productive.

A monolithic type pour makes for a air tight build due to the ICF air tightness it increases the insulation effective value to its true rating.

The Nudura forms are well designed. They come in 18 x 96 inch assembled forms that swing shut to save on shipping space and are available with 4 to 12 inch core sizes.

The plan is too hire a 1 or two people and build the house myself / hire sub contractors when needed.

pinballlooking · 08-15-17, 10:55 AM

I really like ICF construction. People that have very severe weather here seem to go that way.
I really considered building my greenhouse back and ½ side walls with ICF. Take lots of pictures along the way it sounds like a big but great project

jeff5may · 08-16-17, 12:49 AM

The equal thickness forms can be put together forwards, backwards, or sideways and still fit. More generic and universal ensures easier assembly for the not so strong in the brain. Less possible mistakes equals better chance for success.

Adding extra insulating layers on the exterior has lots of benefits. The two more important are as follows:
1. Dew point and freezing point moves into exterior foam layer
2. Enclosed concrete adds thermal mass to the inside of the house

ecomodded · 08-17-17, 04:42 AM

My thoughts exactly they are idiot proof and thermal mass is where its at

Those nudura forms i have my eye on are the same way they are reversible including the corners there is no left or right you flip it over and your good to go.
I'm inching closer to making this reality everyday me and a hired carpenter are finishing the last of the house issues then i list in a month , houses are selling like hot cakes in our city / town right now. . Its a sellers market big time

From here its a parcel of land and and off grid ICF house.

My latest technical crossroad is to use 6 inch thick walls or just 4 inch

Right now I feel confident / optimistic the cost of extra cement would be worth the thermal mass it provides. It makes sense to my common sense anyways.

oil pan 4 · 08-17-17, 09:21 PM

At 4 inches 1 cubic yard will make 9 to 10 feet of wall. If you go to 6 inches thick 1 yard will pour about 6 feet of wall.
Assuming the wall is 8 feet tall.

ecomodded · 08-17-17, 10:02 PM

Thanks oil pan 4 , havent done the math on that or pricing the pour.
Still getting a grip on the process and thinking on plans. It will be a small rancher.
Im going to price out a 1100 sq ft house and a 1350

6 divided by 1100 is 183 cu yards then I add inside walls I'll work on that math

1350 sq.ft is 225 cu yards plus the inside walls

Watched some instructional videos out by the manufacturer and it looks easy enough.

Current project I removed a 4 ft garage extension with a deck ontop from the front of the house and am remounting the garage door flush with the house.

This work was done in the last 3 days.

It was a rot problem not anymore. Swapped out the 2x4 wall for a 6x6 outside wall. It seemed a little precarious with the 2x4's .. its covered in 3/4" plywood for its structural strength.

The door is going and a 3'6" inch slider window is going in place.

ecomodded · 08-18-17, 12:24 AM

Math for 1000 sq.ft ranchers inside and out walls is 195 feet ( not including the footings )

Im not sure on the concrete mix at the moment using the Self Consolidating Concrete Interior Columns and Slabs mix its 50 MPa @ 56 days costs 225 m3 , Im still working on the total but it seems like $7300 bucks

~~~~~~~~~

Im trying this again this time using a ICF manufacturer method

6.25” WALLS
STEP 1: Take the square footage of all wall area and subtract the square footage of all window and door openings.
STEP 2: Multiply by 0.521ft (the width of the cavity) to get the cubic feet of concrete required

STEP 3: Divide by 27cf to determine the yards of concrete required (or divide by 35.32 to determine meters required)
Example: 1845sf of wall area minus 322sf of window and door are equals 1523sf of net wall area. 1523sf times 0.521ft equals 793cf divided by 27cf per yard equals 29.4 yards of concrete Or divide 793cf by 35.32 for meters required. In this case, 22.5.

With a 1000sq.ft rancher inside wall included it works out to 46 m3

$225 m3 x 46 m3 = $10,350

It sounds too good to be true.I'll price the footings roof and forms tomorrow

jeff5may · 08-18-17, 08:49 AM

Yeah, I am not a fan of the ground floor garage crammed in under living spaces above. In densely populated (urban) areas, square footage is a luxury that may not exist, so the home must be configured that way in order to happen. In most other scenarios, I would gladly sacrifice some yard space for a separate garage footprint. Then again, I actually park cars and do projects in the garage constantly. If the space is being used mainly for storage, rather than a working/activity area, it can be utilized as thermal mass for the rest of the structure. They do make good jam rooms as well if you're musically inclined.

I agree that the extra couple inches of wall space is almost too good to be true. The extra thermal mass and structural integrity is worth it on its own. For a DIY project, the ICF method is awesome. Most forms have channels built in for rebar and caps and corners and such, so the guesswork factor goes way down. No massive pouring forms to remove afterwards, no lugging hundreds or thousands of precast blocks, just lots of labor involved with super lightweight styrofoam. Less injury potential for sure. If a certain detail needs rework to be perfect, it can be seen (and modified) before the interior is filled.

08-14-17, 06:21 PM	#1
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	ICF insulation improvement ? Im preparing to build a passive ICF rancher with a crawl space next year could use some schooled advice on the insulated blocks insulation and condensation. The blocks use 2 inches of insulation for both the inner and outer wall so the center of the wall is the cold/warm meeting point. Do they do this to prevent condensation or just ease of manufacture ? Im thinking (oh no) I want to add an additional 2 inches of insulation to the outside wall to push the meeting point to the outside of the concrete instead of the inside as designed. My worry is it will cause condensation to form on the outside of the concrete wall and insulation face causing mildew ? could use tips or advice what do you think , 4 inches insulation on the outside concrete wall 2 inches on the inside is a good idea or bad ? __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

08-15-17, 10:46 AM	#3
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	Nudura forms I was reading that many people use thicker insulation on the outside all the way up to 12 inches thick in some cases. Not sure why manufactures design these with equal thicknesses of insulation seems counter productive. A monolithic type pour makes for a air tight build due to the ICF air tightness it increases the insulation effective value to its true rating. The Nudura forms are well designed. They come in 18 x 96 inch assembled forms that swing shut to save on shipping space and are available with 4 to 12 inch core sizes. The plan is too hire a 1 or two people and build the house myself / hire sub contractors when needed. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

08-15-17, 10:55 AM	#4
pinballlooking Super Moderator Join Date: Jun 2013 Location: SC Posts: 2,923 Thanks: 172 Thanked 564 Times in 463 Posts	I really like ICF construction. People that have very severe weather here seem to go that way. I really considered building my greenhouse back and ½ side walls with ICF. Take lots of pictures along the way it sounds like a big but great project __________________ Current project Aquaponics system , Passive Solar Greenhouse build To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Solar Install 12.5 Kwh- To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Mini Split installs - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. EV Chevy Volt - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

08-17-17, 04:42 AM	#6
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	My thoughts exactly they are idiot proof and thermal mass is where its at Those nudura forms i have my eye on are the same way they are reversible including the corners there is no left or right you flip it over and your good to go. I'm inching closer to making this reality everyday me and a hired carpenter are finishing the last of the house issues then i list in a month , houses are selling like hot cakes in our city / town right now. . Its a sellers market big time From here its a parcel of land and and off grid ICF house. My latest technical crossroad is to use 6 inch thick walls or just 4 inch Right now I feel confident / optimistic the cost of extra cement would be worth the thermal mass it provides. It makes sense to my common sense anyways. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by ecomodded; 08-17-17 at 05:31 AM..

08-17-17, 10:02 PM	#8
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	Thanks oil pan 4 , havent done the math on that or pricing the pour. Still getting a grip on the process and thinking on plans. It will be a small rancher. Im going to price out a 1100 sq ft house and a 1350 6 divided by 1100 is 183 cu yards then I add inside walls I'll work on that math 1350 sq.ft is 225 cu yards plus the inside walls Watched some instructional videos out by the manufacturer and it looks easy enough. Current project I removed a 4 ft garage extension with a deck ontop from the front of the house and am remounting the garage door flush with the house. This work was done in the last 3 days. It was a rot problem not anymore. Swapped out the 2x4 wall for a 6x6 outside wall. It seemed a little precarious with the 2x4's .. its covered in 3/4" plywood for its structural strength. The door is going and a 3'6" inch slider window is going in place. Attached Thumbnails __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by ecomodded; 08-17-17 at 10:44 PM..

08-14-17, 10:25 PM	#2
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	2 inch foam panels are rated for about R-6.5 I have never seen any complaints about condensation. I think ICF construction is a great idea.

08-16-17, 12:49 AM	#5
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	The equal thickness forms can be put together forwards, backwards, or sideways and still fit. More generic and universal ensures easier assembly for the not so strong in the brain. Less possible mistakes equals better chance for success. Adding extra insulating layers on the exterior has lots of benefits. The two more important are as follows: 1. Dew point and freezing point moves into exterior foam layer 2. Enclosed concrete adds thermal mass to the inside of the house

08-17-17, 09:21 PM	#7
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	At 4 inches 1 cubic yard will make 9 to 10 feet of wall. If you go to 6 inches thick 1 yard will pour about 6 feet of wall. Assuming the wall is 8 feet tall.

08-18-17, 12:24 AM	#9
ecomodded Supreme EcoRenovator Join Date: Sep 2012 Location: Vancouver Island,Canada. Posts: 1,037 Thanks: 116 Thanked 100 Times in 87 Posts	Math for 1000 sq.ft ranchers inside and out walls is 195 feet ( not including the footings ) Im not sure on the concrete mix at the moment using the Self Consolidating Concrete Interior Columns and Slabs mix its 50 MPa @ 56 days costs 225 m3 , Im still working on the total but it seems like $7300 bucks ~~~~~~~~~ Im trying this again this time using a ICF manufacturer method 6.25” WALLS STEP 1: Take the square footage of all wall area and subtract the square footage of all window and door openings. STEP 2: Multiply by 0.521ft (the width of the cavity) to get the cubic feet of concrete required STEP 3: Divide by 27cf to determine the yards of concrete required (or divide by 35.32 to determine meters required) Example: 1845sf of wall area minus 322sf of window and door are equals 1523sf of net wall area. 1523sf times 0.521ft equals 793cf divided by 27cf per yard equals 29.4 yards of concrete Or divide 793cf by 35.32 for meters required. In this case, 22.5. With a 1000sq.ft rancher inside wall included it works out to 46 m3 $225 m3 x 46 m3 = $10,350 It sounds too good to be true.I'll price the footings roof and forms tomorrow __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by ecomodded; 08-18-17 at 02:12 AM..

08-18-17, 08:49 AM	#10
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	Yeah, I am not a fan of the ground floor garage crammed in under living spaces above. In densely populated (urban) areas, square footage is a luxury that may not exist, so the home must be configured that way in order to happen. In most other scenarios, I would gladly sacrifice some yard space for a separate garage footprint. Then again, I actually park cars and do projects in the garage constantly. If the space is being used mainly for storage, rather than a working/activity area, it can be utilized as thermal mass for the rest of the structure. They do make good jam rooms as well if you're musically inclined. I agree that the extra couple inches of wall space is almost too good to be true. The extra thermal mass and structural integrity is worth it on its own. For a DIY project, the ICF method is awesome. Most forms have channels built in for rebar and caps and corners and such, so the guesswork factor goes way down. No massive pouring forms to remove afterwards, no lugging hundreds or thousands of precast blocks, just lots of labor involved with super lightweight styrofoam. Less injury potential for sure. If a certain detail needs rework to be perfect, it can be seen (and modified) before the interior is filled.