Tag Archives: foam plastic 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.

Rigid Foam Plastic Insulation

One of the joys of what I do is I get to learn new things every day. I’ve often thought to myself, the day I stop learning, is the day I am dead.

In today’s lesson….one of our clients has taken his engineer sealed plans to his Building Department to obtain a building permit. The building is designed with interior steel liner panels (not my personal favorite choice – but a topic for a future blog). The panels are to cover fiberglass insulation.

Sounds pretty straight forward so far, at least to me…..

Until our client told the Plans Examiner he is going to insulate the building using rigid foam plastic insulation.

What is rigid foam plastic insulation? An example would be Rmax’s R-Matte Plus-3, which is a rigid foam plastic thermal insulation board composed of environmentally sound, closed cell, polyisocyanurate foam bonded to a durable white-matte (non-glare) aluminum facer and a reflective reinforced aluminum facer. Basically – any polyisocyanurate sheathing.

The plans examiner came up with the following, “…foam plastic shall be separated from the interior of a building by an approved thermal barrier of 0.5-inch gypsum wallboard or equivalent thermal barrier material that will limit the average temperature rise of the unexposed surface to not more than 250 degrees F after 15 minutes of fire exposure, complying with the standard time-temperature curve of ASTM E 119…”

In layman’s terms, if your idea is to insulate your new pole building using polyisocyanurate insulation boards, plan upon having to place ½” drywall on the inside wall. This may result in costs which were not budgeted for, not just for the drywall, but to have the framing and weight capacity of the building designed to be able to support it.

My recommendation? Compare total costs between this and other options, such as fiberglass, before making a commitment to rigid foam plastic insulation.  It’s not that it is a bad choice – not at all.  It’s just that your building needs to be designed to support it.  And of course, your buildings need to meet the code for it so your plans examiner is in happy-land.