Gatz Construction provides basic renovation tips to help you with certain tasks around your home.
Good insulation helps keep your home warm in the winter and cool in the summer. It will also help to reduce utility bills and reduce the equipment sizing for your home. Many different types of insulation are out there, fiberglass batts (pink or yellow), blown-in or damp-spray cellulose, rigid foam board (EPS – Expanded polystyrene, XPS – Extruded Polystyrene and PIR – Polyisocyanurate, open-cell and closed-cell polyurethane are really the options right now for residential construction. So each type of insulation has it’s own purpose, pros and cons to using in your home. Depending on local building codes and current state of existing home or new home design will also have an effect of which type of insulation will be used and why.
Costs
$ – Fiberglass Batts
$$ – Blown-In or Damp-Spray Cellulose
$$$ – Open-Cell Polyurethane & Rigid Foam Board
$$$$ – Closed-Cell Polyurethane
Pros
Fiberglass Batts – Cheapest on market, readily accepted, DIY
Blown-In / Damp-Spray Cellulose – Great sound deading properties, good R-value/inch, great for attic space it will fill in small uneven areas, blow-in for attics, and damp-sprayed for wall cavities, excess can be re-used with virgin material, Mold resistant (with Borate content)
Rigid Foam Board – R-value does not degrade with time, double the thickness doubles the R-Value, available in foil, polyethylene or kraft-paper facings, reduces air infiltration, flexible design for exterior and interior use. Common Applications – Frost Protection for Foundations, Slab-on Grade (Vertical & Horizontal application per code), Finished Basements, Roof Insulation, Siding Underlayment and Sheathing.
Open-Cell Polyurethane – R-Value of 3.5 – 3.8 / inch depends on supplier, Low density, expands 30 to 100 times.
Closed-Cell Polyurethane – OUR PREFERENCE WHEN POSSIBLE – R-Value – 6.5 – 6.9 / inch, acts as a vapor retarder / moisture control, adds to rigid strength of building, very flexible in applying in tight spaces (crawl space, rim joists, cantilever, cathedral ceilings, etc.), exceptional air sealing capabilities, fills cracks and voids and expands when sprayed, great for renovations where existing framing structure does not allow for R-value with blow-in or fiberglass batt insulation.
Cons
Fiberglass Batts – Quality Control – Easy to compress therefore de-valuing the R-value/inch, need 6-mil Vapor Barrier on warm side of wall, hard to insulate rim joist & cantilever cavities after framing is complete, Difficultly in cathedral ceiling. In Michigan, to use fiberglass batt insulation in walls, you will need 2? x 6? wall framing, otherwise it will not pass code.
Blown-In / Damp-Spray Cellulose – Costs more than fiberglass, needs more prep time (cleaning floors really good, taping over electrical outlets, etc.), drying time should be within 24 hours after installation, clean-up.
Rigid Foam Board – Permeability to moisture, Insect Infestation (termites and wood boring insects find easy nesting – particularly in below grade applications, but there are treatments for this), UV Exposure degrades the material and its performance.
Open-Cell Polyurethane – Costs, needs a vapor barrier, needs deeper stud bays to reach local R-Value Codes
Closed-Cell Polyurethane – Costs, not a silver bullet, but offers so much more for the money.
Last word on this, do not get sold on the sales pitch of spraying in 1″ or whatever of closed cell and then using fiberglass batts or Damp-spray cellulose for the walls to reach the code R-value for your walls. My personal opinion, with the closed cell polyurethane creates a vapor barrier, then you install something else next to it that may or may not seal up to it just to save a dime, is not the correct idea, save the money somewhere else. It will pay-off in the long run!
