When we installed the exhaust fan for the new basement bathroom, the most direct exit route was right through the rim joist of the house. Dad got out his trusty hole saw with the largest (4 inch diameter) attachment and got to work on it.
The plug we pulled out shows just what my walls are made of.
Note: it might have been easier to do this BEFORE we sealed the rim joists with 4 inches of rigid insulation but … we didn’t think of it then. So we had to go right through that as well.
When we got all the way through we had a fascinating cross section of the house to show for it.
Here we have: the aforementioned (new) rigid insulation, the 2×10 rim joist, 3/4 inches of pressed fiberboard, a layer of tar paper, and the lapped wooden siding.
It is pretty shocking that the main floor wall cavity has no more insulation than that 3/4 inches of press board but that’s the way most houses were built in the 50’s.
If you’re curious about housing insulation and air tightness technology and how they’ve developed over the years, check out this great This Old House video on the subject of house wrap!
My own ranch is actually relatively air-tight, per our blower door test. This is largely thanks to the interior paint layer which was well applied and hasn’t cracked over the years and also to the recent installation and good air-tight seal of the new windows. However the insulation could absolutely stand to be improved.
How to Improve the insulation on your ranch house
Fill the Walls
I could drill holes into each wall stud cavity and have foam or fill insulation blown in, then plug and patch them. This is the best way to improve wall insulation without disturbing the home’s exterior but it can be problematic because not every stud cavity is continuous … blocking can get in the way of full insulation coverage, leaving stubborn cold patches.
Wrap the Walls
Another way to boost the insulation value of your house’s walls it to wrap them with insulation from the outside. If you are planning to replace your homes siding (and ideally also the windows) you can thicken the house’s exterior walls by adding one or several overlapping layers of rigid insulation to the exterior. This is a great way to improve the air seal and R-value of the house with minimal interruption of life inside.
Mind the gaps
Air seal can be almost as important as insulation for keeping your house as warm, cool or dry as you’d like it to be. Look out for sneaky leaks in cracked room corners, behind outlets or switch plates and ceiling light fixtures, and at every window and door. You can also seal the unfinished areas of your house – particularly where the foundation meets the framed structure.
A few hours spent on a cold day, feeling for cold air currents and sealing gaps with a can of spray foam can be time very well spent. If you want to go further, arrange for a blower door test with a local energy improvement company!
Cap the ceiling
One of the most effective – and least invasive – ways to improve your home’s temperature is to properly vent and insulate your attic. Even if you peek in your attic and see some insulation, you can always do better with both air seal and layers of R value. In the winter you want to stop heat from rising right out of your living space, you want the ceiling of your house to be the highest warm spot. The “cool roof” idea means that your roof can collect snow and actually IMPROVE – think igloos – its insulation in the coldest weather. In summer you want a well vented roof to let any hot air collecting when the sun hits your home rise right back out again, not stick around to warm your living space. Again, a crew can come in to seal and insulate an attic with little interruption to life inside so this is a great solution to improve your energy efficiency without remodeling your whole life.
Line the basement
One last place to focus on both air seal and insulation retrofits is the the basement. Sealing and insulating the rim joist is particularly high value since that is often a place where only a 2×10 and some siding stand between you and the outside world. The best practice for warming up the whole basement is to air seal right against the concrete with a well taped layer of rigid 1″ foam insulation, then build a framed 2×4 wall inside that and fill it with batt insulation. Read about how I took that on here, here and here.
Now you know what you need to warm up your ranch. What will you take on first?