Tag Archives: stone wool insulation

Termite Resistance of Stone Wool Insulation

Termite Resistance of Stone Wool Insulation

Could you possibly share whatever information you might have on a product that is termite proof/termite resistant to insulate my slab on my building.

The only thing I have found somewhat useful is Cellofoam. It’s a EPS product that is infused with insecticide.”

Mike the Pole Barn Guru says:

Solution – Rockwool Comfortboard 80.

Rockwool Technical Innovations released a bulletin in August 2019, wherein they had recently completed third party testing at University of Hawaii to determine termite resistance of stone wool insulation. Insulation samples were tested to AWPA E1-09, “American Wood Protection Association Standard Method for Laboratory Evaluation to Determine Resistance to Subterranean Termites”. Test involved exposing insulation samples to 400 Formosan subterranean termites for a 28-day period then measuring weight loss of material, termite mortality rates and visually evaluating sample damage. Results were then compared to a control sample of Southern Yellow Pine untreated and Southern Yellow Pine treated for termite resistance with ACQ, type D.

Test results indicated stone wool insulation proved to be termite resistant per this rigorous test making material appropriate for use under conditions of very heavy termite hazards.

Laboratory observations made during testing moted termites initially investigated stone wool, but then covered it with sand within first week. This is an avoidance behavior evidenced by termites wanting to isolate something undesirable, such as an unacceptable food material.

Material weight loss of stone wool was only 1.22% compared to 4.85% for treated wood and 50.92% for untreated wood.

Both IRC (International Residential Code) and IBC (International Building Code) address foam plastic insulation use in areas where termite infestation probability is ‘very heavy’ and restrict its use when installed on exterior face or under interior or exterior foundation walls or slab foundations located below grade. To use foam plastics in these applications and geographies, it is required all structural members are made of non-combustible materials or pressure preservative treated wood, or an approved method of protecting foam plastics and structure from termite damage is used.

Texas Post Frame Barndominium Insulation

Reader KIMBERLY in LINDEN writes:

“We are building a 52x40x10 post frame home in East Texas.  The entire thing will be living space.  I have been researching as much as possible on the best way to insulate a post frame home with metal siding and roof.  The information is overwhelming and you get a completely different answer depending on who you talk to.  I know not to skimp on insulation, but the consensus on most “barndominium” FaceBook groups is that spray foam is the only way to go.  I have reservations about that, because it may be a superior way to insulate, but it depends almost exclusively on who is doing the actual foam application.  On top of that you need to spend more money on your HVAC system to add the proper ventilation/air exchange.

I want a well insulated home that is specific to the type of building material and location we live in.  To me, “not skimping” on insulation doesn’t mean that it has to be the most expensive insulation either.  

I also know the insulation world is constantly changing and evolving, but what would your recommendation be to insulate our home in East Texas?

Thank you so much for your time!”

Mike the Pole Barn Guru responds:

Your insulation requirements will vary depending upon where you are in East Texas. Climates zone 1 (closest to Gulf) require R-30 ceilings, R-13 walls. Zone 2 requires ceilings to be R-49 and zone 3 (farthest north) goes to R-20 walls. You can look up you county’s climate zone here: https://codes.iccsafe.org/content/IECC2021P1/chapter-3-re-general-requirements#IECC2021P1_RE_Ch03_SecR301. I will cheat for you and tell you Cass County is Climate zone 3A.

For sake of discussion we will assume you have a dead attic space and will be insulating directly above a finished ceiling.  I would ventilate your dead attic space at the eave (air intake) and the ridge (air exhaust). Make provisions for preventing condensation on the underside of roof steel by having some sort of a thermal break. My personal preference is by using an Integral Condensation Control (https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/).  You will want to order roof trusses with raised heels (https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/), so you can get full insulation depth from wall-to-wall with blown in fiberglass. Heel height should be R value of insulation divided by three and add two inches so you can achieve adequate airflow above insulation.

Should you want to condition your attic – delete ventilation, raised heels and the Integral Condensation Control. I would apply closed cell spray foam two inches to the underside of roof steel, then add open cell spray foam to desired R value.

For walls – best results will be from two inches of closed cell sprayed to inside of wall steel, then fill balance of wall cavity with either open cell spray foam, or unfaced batts (ideally stone wool https://www.hansenpolebuildings.com/2013/03/roxul-insulation/). You could also use BIBs to fill (https://www.hansenpolebuildings.com/2011/11/bibs/). Do not place a Weather Resistant Barrier (WRB) under wall steel or a vapor barrier on inside of wall.

As an alternative to spray foam, you can use a WRB between framing and wall steel, then BIBs with an interior vapor barrier or faced batt insulation.

Energy costs are not going to go down, so I would encourage you to err towards more insulation rather than less – and (since most heat loss is upward) invest more into added ceiling insulation than walls.

In warmer, humid climates like yours, your HVAC system should include an Energy Recovery Ventilator (ERV) regardless of what your choice of insulation systems ends up being.