Remodeling the office (new floor, ceiling & adding insulation) passive house retrofit

Daox · 08-08-11, 09:47 AM

This weekend we took our first step toward remodeling our office. We've been talking about doing this since we bought the house. All of the 1st floor rooms have been remodeled except this one. It has some pretty beat up and stained carpet that is falling apart in places. The ceiling is also pealing due to some water damage that was done years ago from the previous owners. The problem has been fixed long ago thankfully. Also, I don't think that the exterior wall is insulated at all besides the thin piece of foam under the siding outside.

Anyway, the first step was picking up the new flooring. I'll be adding hydronic heat to the floor and will be putting bamboo over it. We picked up the bamboo this weekend. Its semi-thin (around 1/2" I'd guess) tongue and groove pieces.

I'll get pics of all this stuff up later.

AC_Hacker · 08-08-11, 11:14 AM

Quote:

Originally Posted by Daox

I'll be adding hydronic heat to the floor and will be putting bamboo over it.

I am very interested in how you approach this phase of your re-model.

As I recall, you already have fossil -fueled hydronic heating in part of your house.

And your solar panel rack and heat storage tank, both seem aimed at solar space heating... and may likely have lower temperature heat available to you.

I have experimented with Watts Radiant RadiantWorks and have found it very interesting and useful, especially when doing some 'what-if' trial runs. It has helped me understand how varying certain parameters can affect the system performance.

As for myself, I am beginning to favor the use of 3/8" PEX, spaced much closer than usual (3" or 4"), using a multi-tube spiral arrangement, as illustrated below.

...I am also favoring aluminum spreader plates like Gary's floor, topping the plates with 1/4" Hardibacker and finishing the floor with Marmoleum, which has very low R-value.

Best of luck with your project.

-AC_Hacker

Daox · 08-08-11, 12:09 PM

Right now I have electric/hydronic heat since my gas tank water heater died. The only form of hot water I have right now is my on demand electric unit that is just enough for a shower. I do not plan on using it to heat the house this winter. I do plan on having the solar setup done before winter rolls around though and it will run off of that and the natural gas forced air.

But, I am unsure how I am going to do the floor. I am definitely leaning toward not pouring the floor in concrete and using the aluminum spreaders like Gary. I have not played around with tubing sizes though. I'll have to do some more reading through the DIY hydronic floors thread to catch up on whats being done. However, I do know I want close spacing so I can fully utilize the solar hot water for heating purposes. I'll definitely have to check out that link. Any suggestions are welcome.

gasstingy · 08-08-11, 01:45 PM

I've usually kept this type of comment to myself on topics where people are remodelling, but I'm going to throw it out there anyway and will shut up if it's not appreciated.

FWIW: I'd strip the drywall off of the outside walls, inspect for wood damage and check out the wiring and then I'd have spray foam insulation sprayed to fill the cavity. Instant vapor barrier and best available insulation. Add new drywall, finish it, paint it and feel good about my work. I can't help but believe it would be more than worth it over the long term, unless I were planning to move really soon. Even then, with some photos of the open walls, it might be a great selling point to someone who was afraid of how much it would cost to heat and cool.

Daox · 08-08-11, 02:02 PM

Definitely don't keep it to yourself!

I'm actually planning on doing a bit more than that. This one room will help me determine what I'll be doing to my upstairs which also needs hydronic flooring and wall insulation.

The current plan is to do something to further insulate the wall beyond just normal fiberglass batts. Spray foam is a great start for sealing purposes. Perhaps I'll try one of those DIY kits. However, beyond that, I'll also be thickening the wall. I'd like to end up with an R40 wall once everything is said and done, but I think that may be a bit much to ask for. I might have to settle with around R30. Since a traditional wall 2x4 wall is only ~R11 once you take into consideration the thermal bridging, that is quite a step up. I'm thinking of something similar to the mooney wall. I don't know how deep I'm going to make the wall yet though.

gasstingy · 08-08-11, 02:23 PM

OK, let's go one step farther then. After the wall is spray foamed, before you drywall it, you add a layer of extruded polyeurethane in your choice of thickness. I know it comes in 1/2" up to 2" in my area. This takes care of that thermal bridging problem at the cost of a very minimal amount of lost room dimension. While the sprayed insulation + sheet foam insulation may not bring your number quite up to R40, I'd bet it would be quite nice and cozy.

OTOH, to meet passive house standards, mooney walls are probably the best choice. It's hard to beat a 14" or thicker wall with blown in insulation. In my area at least, homes as old as yours typically have large enough rooms that would accept a mooney wall setup without feeling cramped, with the likely exception of the bathroom.

I'll be following along on whichever choice you make.

S-F · 08-09-11, 08:39 AM

I suggest you get some recycled polyiso, cut it to fit the cavities and spray foam it in place. That will give you a good air seal and an immediate R 16. Then I'd Larsen truss to the inside with plywood gussets and 2x3's and dense pack. You could easily get R 40 that way and it would be a lot cheaper/healthier than a full load of spay foam with a much higher R value.

gasstingy · 08-09-11, 08:57 AM

S-F said

Quote:

You could easily get R 40 that way and it would be a lot cheaper/healthier than a full load of spay foam

I'm not doubting you, but I'd love to read up on the research that speaks of health issues by spray foaming. If spray foaming is unhealthy, I'd sure like to take a different route than my current plans.

Daox · 08-09-11, 09:05 AM

Quote:

Originally Posted by S-F

I suggest you get some recycled polyiso, cut it to fit the cavities and spray foam it in place. That will give you a good air seal and an immediate R 16. Then I'd Larsen truss to the inside with plywood gussets and 2x3's and dense pack. You could easily get R 40 that way and it would be a lot cheaper/healthier than a full load of spay foam with a much higher R value.

Even with 2 inches of polyiso I'm not seeing how I can get R16?

Larsen truss is a great idea that is also in the ol noggin for this project. I'm just not sure exactly how much I want to thicken the wall yet.

The current wall is 4" thick (old rough cut lumber). I'd definitely be willing to double that, and I think even add up to 6" (10" total thickness) to the insulation cavity (so drywall = extra). If I did two inches of polyiso foamed in place, and blow the rest in cellulose, that would get me to ~R40.

The other thing is that I do not have 6" to spare in the upstairs. The rooms are already pretty small and the less room I loose the better.

S-F · 08-09-11, 09:17 AM

Most of the recycled sheets of polyiso are 2.25" which are something like R 15.7. They are called R 16 boards.
There is a growing body of evidence suggesting that spray foam , while nothing like UFFI, may still have some negative qualities. The catch is that once it cured it's supposedly completely neutral, but only when mixed properly. Apparently when it's not mixed properly there can be a lot of issues. And also it appears to be pretty difficult to get the mix correct. Even for seasoned professionals.

And besides, cellulose is awesome. Sure the R value is a little bit lower but the other benefits are fantastic. The hygroscopic value of it is amazing. I wish my walls were 12" of cellulose. It's also probably the greenest insulation there is.

08-08-11, 09:47 AM	#1
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Remodeling the office (new floor, ceiling & adding insulation) passive house retrofit This weekend we took our first step toward remodeling our office. We've been talking about doing this since we bought the house. All of the 1st floor rooms have been remodeled except this one. It has some pretty beat up and stained carpet that is falling apart in places. The ceiling is also pealing due to some water damage that was done years ago from the previous owners. The problem has been fixed long ago thankfully. Also, I don't think that the exterior wall is insulated at all besides the thin piece of foam under the siding outside. Anyway, the first step was picking up the new flooring. I'll be adding hydronic heat to the floor and will be putting bamboo over it. We picked up the bamboo this weekend. Its semi-thin (around 1/2" I'd guess) tongue and groove pieces. I'll get pics of all this stuff up later. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

08-08-11, 12:09 PM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Right now I have electric/hydronic heat since my gas tank water heater died. The only form of hot water I have right now is my on demand electric unit that is just enough for a shower. I do not plan on using it to heat the house this winter. I do plan on having the solar setup done before winter rolls around though and it will run off of that and the natural gas forced air. But, I am unsure how I am going to do the floor. I am definitely leaning toward not pouring the floor in concrete and using the aluminum spreaders like Gary. I have not played around with tubing sizes though. I'll have to do some more reading through the DIY hydronic floors thread to catch up on whats being done. However, I do know I want close spacing so I can fully utilize the solar hot water for heating purposes. I'll definitely have to check out that link. Any suggestions are welcome. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 08-08-11 at 12:13 PM..

08-08-11, 02:02 PM	#5
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Definitely don't keep it to yourself! I'm actually planning on doing a bit more than that. This one room will help me determine what I'll be doing to my upstairs which also needs hydronic flooring and wall insulation. The current plan is to do something to further insulate the wall beyond just normal fiberglass batts. Spray foam is a great start for sealing purposes. Perhaps I'll try one of those DIY kits. However, beyond that, I'll also be thickening the wall. I'd like to end up with an R40 wall once everything is said and done, but I think that may be a bit much to ask for. I might have to settle with around R30. Since a traditional wall 2x4 wall is only ~R11 once you take into consideration the thermal bridging, that is quite a step up. I'm thinking of something similar to the mooney wall. I don't know how deep I'm going to make the wall yet though. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 08-08-11 at 02:07 PM..

08-08-11, 01:45 PM	#4
gasstingy Journeyman EcoRenovator Join Date: Feb 2010 Location: Arab, AL Posts: 491 Thanks: 109 Thanked 49 Times in 43 Posts	I've usually kept this type of comment to myself on topics where people are remodelling, but I'm going to throw it out there anyway and will shut up if it's not appreciated. FWIW: I'd strip the drywall off of the outside walls, inspect for wood damage and check out the wiring and then I'd have spray foam insulation sprayed to fill the cavity. Instant vapor barrier and best available insulation. Add new drywall, finish it, paint it and feel good about my work. I can't help but believe it would be more than worth it over the long term, unless I were planning to move really soon. Even then, with some photos of the open walls, it might be a great selling point to someone who was afraid of how much it would cost to heat and cool.

08-08-11, 02:23 PM	#6
gasstingy Journeyman EcoRenovator Join Date: Feb 2010 Location: Arab, AL Posts: 491 Thanks: 109 Thanked 49 Times in 43 Posts	OK, let's go one step farther then. After the wall is spray foamed, before you drywall it, you add a layer of extruded polyeurethane in your choice of thickness. I know it comes in 1/2" up to 2" in my area. This takes care of that thermal bridging problem at the cost of a very minimal amount of lost room dimension. While the sprayed insulation + sheet foam insulation may not bring your number quite up to R40, I'd bet it would be quite nice and cozy. OTOH, to meet passive house standards, mooney walls are probably the best choice. It's hard to beat a 14" or thicker wall with blown in insulation. In my area at least, homes as old as yours typically have large enough rooms that would accept a mooney wall setup without feeling cramped, with the likely exception of the bathroom. I'll be following along on whichever choice you make.

08-09-11, 08:39 AM	#7
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	I suggest you get some recycled polyiso, cut it to fit the cavities and spray foam it in place. That will give you a good air seal and an immediate R 16. Then I'd Larsen truss to the inside with plywood gussets and 2x3's and dense pack. You could easily get R 40 that way and it would be a lot cheaper/healthier than a full load of spay foam with a much higher R value.

08-09-11, 09:17 AM	#10
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	Most of the recycled sheets of polyiso are 2.25" which are something like R 15.7. They are called R 16 boards. There is a growing body of evidence suggesting that spray foam , while nothing like UFFI, may still have some negative qualities. The catch is that once it cured it's supposedly completely neutral, but only when mixed properly. Apparently when it's not mixed properly there can be a lot of issues. And also it appears to be pretty difficult to get the mix correct. Even for seasoned professionals. And besides, cellulose is awesome. Sure the R value is a little bit lower but the other benefits are fantastic. The hygroscopic value of it is amazing. I wish my walls were 12" of cellulose. It's also probably the greenest insulation there is.