Spray foam insulation

[Yellowknife]

Curious, I read that a sealed house is a sick house? Airflow needed to prevent mold etc. etc. I know it was used alot in Canada before here in the US. I like the idea , but not sure.

Airflow is needed... but far better off to have it controlled, conditioned and filtered, rather than just leaking around windows and outlets. A modern house, built tight, will have mechanical ventilation. There are various ways to do it, but IMO a well sealed house with a Heat Recovery Ventilators (HRV) or Energy Recovery Ventilators (ERV) is the ideal for northern climates. I'm sure there is a version of that for the southern humid climates as well.

The amount of mold and rot that can develop in an old leaky northern house has to be seen to be believed.

 

[SCHUNTER73]

If you are in an area that has termites, do your homework.

 

[Beendare]

Airflow is needed... but far better off to have it controlled, conditioned and filtered, rather than just leaking around windows and outlets. A modern house, built tight, will have mechanical ventilation. There are various ways to do it, but IMO a well sealed house with a Heat Recovery Ventilators (HRV) or Energy Recovery Ventilators (ERV) is the ideal for northern climates. I'm sure there is a version of that for the southern humid climates as well.

The amount of mold and rot that can develop in an old leaky northern house has to be seen to be believed.

Yep...in a sealed home in the south add a dehumidifier to that ERV.

Insulation's effectiveness is easy to check these days with the hand held infrared heat sensors. Put your hand on the sheetrock of a house on a hot/cold day and you can tell it's fiberglass insulation- very little benefit unless the home is wrapped with a foam board.

 

[Coopsdaddy]

How is my Sitka hoodie so much warmer and better at blocking wind than a cheap cotton hoodie?

There's definitely some shady guys running spray foam companies, same as every other small service business...

But science is real, and different chemicals have different R values.

There's a reason we don't build houses the way we did 20 or 40 or 60 years ago...

Well im just saying what I have researched and found.No one said it can’t be done but there’s more to it than just spraying foam.
Your Sitka jacket is 300.00 not 300000.00
Were your rain gear in the wrong application and see how that works out.

 

[Jpsmith1]

Hvac guy here.

Foam insulation is a fantastic choice in terms of R value. I have it in my own home.

I did have to drop size on my HVAC system due to the sizing being wrong. It doesn't impact your HVAC system efficiency. Period.

It also air seals your home. If you relied on a "leaky" building envelope for your fresh air, then yeah, it's gonna 'cause' mold. Your home needs to be ventilated. An ERV/HRV is what would do that for you.

It's not always a simple and direct job, but I count foam insulation as some of the best money I've ever spent on my home.

 

[Yellowknife]

. Put your hand on the sheetrock of a house on a hot/cold day and you can tell it's fiberglass insulation- very little benefit unless the home is wrapped with a foam board.

There are also better ways to do fiberglass than the old cut and fit batts as well. My current house we stapled netting to the studs and blew dense pack fiberglass in behind it. It makes for a near perfect install, with zero cold spots.

 

[IDVortex]

Spray foam is a game changer...IF;
1) the product is mixed right
2) its used correctly

It's not one size fits all- there is open cell and closed cell to be used in different situations. The insulating value of foam is far superior to Fiberglass.

IMO from years of doing this stuff; Loose fiberglass batts is crummy insulation. Rock wool batts and foam is fantastic

If my wife and I ever are able to build our own home, this is what I plan on doing, and I think is the best practice without paying a pretty penny for a solid spray foam.

2in of close cell as my air and moisture barrier, than rock roll to fill in the cavity. Best of both worlds. And I even want to spray foam my attic area with 2in of close cell then either do batts or just do blow in. But I also would love to build a air tight home which is why I'll do spray foam first.

Spray foam is a great product if used in a system. Spraying it in certain areas doesn't always mean you're achieving the products full potential, let alone getting your ROI back from it. Most importantly, use a very well known applicator. Spray foam isn't something you go with the cheapest quote on at all.

 

[def90]

Just like everything else construction wise it all depends. If it's installed correctly based on the structure that is there it's great. If you just go and fill your roof trusses full of it without the proper airflow and so on in the structure then yes you will have problems.

 

[Forestryguy]

You can read up on and listen about spray foam on the FineHomeBuilding website.

 

[Axle]

I have had 3 different roofers tell me there is no way they would recommend spray foam on the bottom of the roof deck, and that the shingle manufactures likely wouldn't warranty the shingle. Our climate zone is a tricky one to build in, as the moisture drives reverse summer to winter. It is easier to optimize if you are all heat and no A/C or all A/C and little to no heat.

I think spray foam can be done right, but it depends on a lot of factors. If it is done wrong, it can cause a lot of problems, but that can be said of any air sealing/insulation. I would recommend talking to a couple different roofers and contractors that have been working in your area for the last 20 years and see what they say. Most of us in the building trades are happy to give our opinion on things.

 

[ihookem]

I have had 2 homes on the same lot. I built a 3 bed. 2200 sq. ft ranch. We did cellulose dense pack in the 2x6 walls and out in about r50 in the attic. We had no air leaks anywhere. Fast forward 4 yrs. Our house has an electrical fire . The house was so smoked out that me and the ins. co. decided it was not worth rebuilding. We tore it down and built a new one on the same basement. We decided to go with 4" closed cell in the walls and we put in more than r50 and likely is r60. We know the new house is easier to heat. It is very quiet in the house too . The wind really has to be blowing to hear it. Had I known it was this easy to heat this house in southern Wisconsin, we wouldn't have bothered with a wood boiler. I figure we could heat it for about $1,200 a year with natural gas. We also spray foamed the basement rim joists between the joists. This is very important. Foam spray between the roof rafters but only a few feet up to prevent ice back damming . We have no ice cycles hanging from the gutters. It was offered but I dont think it was worth the $2,200 to put 1" in the attic. That would have been sprayed over the ceiling drywall, not between the rafters. If foam is sprayed on the bottom roof sheathing , the shigles will get much hotter and will wear out faster. Airflow in the attic keeps the shingles from getting so hot. If you want to save some money, Like one poster does, foam the walls, 2" and then R15 figerglass . The best thing about foam is it stops airflow .. If you get airflow in a wall, the r15 can't do its job cause insulation NEEDS dead air space with no air movement

 

[Joe7296]

Also be careful, insurance providers are starting to say no to closed cell.. great when it works but in the off scenario where it doesn’t I’ve hear of big problems. I’m becoming a big fan of rockwool