Builders Share

Insulation Review

Thanks to Alex for the comment on insulation.  As thing start to cool down here and the furnace starts firing up every morning it's worth reviewing insulation issues.

The upstairs insulation has worked out well. The house is very cozy, though I still need to tighten up the windows.

The 1x3 strapping over the 1" rigid board worked out well too. The only thing I wish I had done was plan a little better for things that might be attached to the walls later (like the wainscoting in the bathroom). If I had been more consistent with my placement of the strapping, I would know exactly where I had something solid to nail to. Maybe I should have gone 16" on center with the strapping instead of 24"?

I'm finding that using the stud finder for locating the strapping isn't easy. The tool gets confused by the studs that are deeper in the wall.

As far as the strapping being sufficient for holding the drywall (with a coat of plaster I might add)--nothing's fallen yet! I think it's a necessary step with insul. board as thick as 1". Without it I think you'd be asking too much from the sheetrock screws. With the downstairs walls I used 1/2" rigid board and no strapping. That's been fine too but the walls have a lower R-value as a result of both the thinner insul. board and the air space provided by the strapping.

Anyway, please go ahead and post comments, and I'll reply as I'm able.  Thanks again, and good luck with your project.

james graham (aka handyman)

Cold Roof, Warm House (Part 2)

After the foam insulation contractors had come and gone, the house had an entirely new feel.  Of course the house was still in its "gutted to the studs" state, and it was March and I wasn't heating the place so it was still cold, but I was surprised at how much quieter the house felt both in terms of sound and air flow.  The hammers banging didn't echo quite as much and whatever heat that was generated by bodies working actually raised the ambient temperature.

Unfortunately, the contractors had left quite a mess.  Despite their promise to use drop cloths, they didn't.  The foam overspray was everywhere.  And even though the house was clearly a construction site which might give some excuse to their negligence, there were bathroom fixtures and original flooring that got covered with foam insulation droplets.  Two years later, I'm still cleaning it off of the upstairs floor. 

Not having worked with many subcontractors to that point, I made the mistake of not supervising them closely.  I tend to want to stay out of the way and let professionals do their work, but the bottom line is that I was paying them.  They came back and cleaned up a reasonable amount of their mess before I mailed the check.

The next task for insulating was sealing up obvious points of infiltration with spray can foam.  As I mentioned in my last post, this is a messy job.  It just  seems impossible to apply this stuff without getting on places you don't want it.

Installing fiberglass batts in the exterior walls was next.  The original walls are timber framing, sheathed in 1" pine.  With this kind of construction, studs are placed only as needed to provide nailers for the sheathing and windows, and to provide support during construction. Knowing that I was going to cover the interior walls with sheetrock, I added more studs for mounting the panels.  In most cases I was able to place the studs 16 inches on center and this allowed me to use the standard size fiberglass batts but there were a lot of places where I had to cut the batts and place them at odd angles to fill all the spaces.

After installing the batts, I then installed 1/2 inch foil-faced foam board over the top of the fiberglass. This not only increases the R-value of the walls but also provides a vapor barrier.  The seams between the foamboard were sealed with foil tape to increase the effectiveness of the vapor barrier.

My efforts were not in vain.  Whereas the prior owners had burned 1300 gallons of fuel oil the last year they were in the house, we burned 475 gallons of fuel oil, and 2 and half cord of wood the first year.  Using today's prices ($2.60/gal oil and $150/cord green wood) we saved $1770 in just the first winter, and that was before insulating the upstairs walls.  (The priority was to get the downstairs in move-in condition before working on the upstairs.)  So far this year, after getting the upstairs insulated, we've only had 200 gallons of oil delivered and I don't expect to burn more than 2 cord of wood.  We might just get out of this winter spending less than $1000 on heating.

Super-insulating the house and relying as much as possible on wood heat is more than just an economical and comfort-based decision.  The battles we're fighting for energy resources are real and far-reaching.  Shrinking our "carbon footprint" is a moral issue as much as it is economical. (At least that's what I keep reminding myself when I'm splitting wood and lugging it into the house.)

handyman

p.s. Check out the following Builders Square animated How-to Tutorials associated with this post:

Climate Control: Insulating an Unfinished Attic
Hanging Drywall

Cold Roof Warm House (Part 1)

This morning the thermometer outside my kitchen window read -20 degrees Fahrenheit.  That's TWENTY BELOW!  Okay, you Canadians shrug, but even for us hearty New Englanders, that's pretty cold, and by March, we're starting to think Spring (or at least Mud Season) so it's not all that welcome.  But thanks to my efforts at bundling-up Chez Melendy early on in the renovation, we're cozy inside.

As I mentioned earlier, one of the principal reasons for gutting my house in the first place was to insulate the walls and ceiling.  There was no insulation in either place for the prior residents.  No cornhusks, newspapers, or rags were found inside the walls, just airspace.  The original walls were covered with plaster, though, and this provided some brake against the cold.  Most of the cold air that enters a house is through infiltration.  Cold air comes through the tiny cracks in the outside walls and then finds its way through the interior walls via electrical outlets, holes for plumbing, window casings, etc.  Plaster does a good job at sealing up the places were infiltration can occur.  But the fact is that the prior residents burned 1,300 gallons of oil the last year they lived in the house.  That's a lot for a smallish (1400 sq. ft.) house. Even if the Melendys had put some pink fiberglass insulation in the upstairs attic they could have cut down a little on the heating costs.

Since I was going all-out to increase the R-Value of my house I decided to hire a contractor to apply polyurethane foam to the rooflines and the sill perimeter.  This would help cut down on the chimney effect of losing heat through the roof while having it replaced with cold air that is drawn in where the foundation comes into contact with the frost line.

The biggest hurdle with polyurethane foam insulation is the cost.  After all, it's a petroleum product and it requires special equipment for application.  There are DIY kits available but I had a large job to do and plenty of tasks to keep me busy, and if you've ever used the spray foam cans, which spray a similar material, you know that applying foam insulation is a messy and unforgiving business.  The pros came in and had the job done in one and a half days.    As much as I prefer to tackle every task on my own, this was one I decided to let go of.

Applying foam to an old house is especially beneficial because of its ability to seal off areas of infiltration while adding R-Value at the same time.  Chez Melendy was sheathed with rough sawn pine boards and then covered in clapboards.  Tyvek building wrap wasn't even part of anyone's imagination at the time, and tarpaper must have been considered a luxury because it wasn't used either.  The foam sealed all those cracks right up.

Another benefit of the kind of foam I used (known as closed cell) is that it saved me from having to vent the roof, which would include cutting vent holes in the soffit and installing a ridge vent. 

The need for venting comes from the fact that in a well-insulated house, moisture can get trapped between the interior and exterior walls and eventually start rotting the wood there.  Think of a cold glass of water on a hot day.  Moisture condenses on the cold glass.  In the winter, moisture from inside the house can condense on the cold roof if no vapor barrier prevents it from getting there.  In the same way, during summer, outside moisture can condense on the out-facing side of the interior walls if the house is kept cool.  Venting the space between the walls provides airflow to help carry this moisture away. 

Closed-cell polyurethane foam provides an automatic vapor barrier, though, so that moisture created by people breathing, taking showers, etc. inside the house can’t pass through to where it might eventually rot the wood sheathing.

In the next installment I’ll write about insulating the walls and how the results of my efforts paid off in the first winter.

handyman

p.s. Check out the following Builders Square animated How-to Tutorials associated with this post:

Climate Control: Installing a Soffit Vent
Climate Control: Installing a Ridge Vent
Climate Control: Insulating an Unfinished Attic