How to Add Insulation Without Ripping Down Walls

Welcome to my little 'ol 1930s cottage bungalow!  I love the character of old houses but I don't love the lack of insulation. There are several ways to add extra insulation to old homes without having to tear down interior walls.  My solution is the least expensive and the cutest (in my humble opinion!)

My house has 2x4 framed outer walls.  At some point in time, cellulose insulation was added to the wall cavities by a company that drills holes near the top of the wall cavities from the outside and inserts the cellulose by blowing it into the cavities.  This doesn't work all that well since not all the wall cavities get found (thanks to extra framing for windows and such).

When I tore down the walls for my bathroom renovation, I found two cavities with no insulation in them at all...

I don't want to tear down all the outer walls and re-insulate, nor do I want to take the siding off the house (newly sided 5 years ago!) to add insulation to the outside.  Both of these solutions are very effective but costly.

My simple solution isn't all that cheap but it is an easy DIY project and saves on the cost of hiring a contractor.  This is how it looks when the job is done:

or this

or this

I use a combination of rigid insulation and bead board paneling applied over the top of the existing walls.  Of course, you don't have to use bead board paneling, you can use any kind of wood or drywall or paneling. You can even use pallets to cover the insulation if that's the look you like.

This method gives me the beefed up insulation, the cute cottage style look that I love and an easy application that requires very few tools.  The only tough part is painting the bead board thanks to all the grooves, but that's not really all that tough to do.

To install the rigid insulation, you simply cut it to size using a utility knife. Use caulking and a caulking gun to glue the insulation to the wall, tape the joints with sheathing tape (like TuckTape) and apply the paneling or drywall or wood over the top of the insulation.  You'll need fairly long nails to get through the insulation and into the studs, so bear that in mind when buying your supplies.  Alternately you can installing furring strips which are 1"x 2" strips of wood hung horizontally  (24" apart) and nailed into the studs.  That way you can easily nail the paneling over the top of the insulation.  Plus if your walls are uneven, the furring strips allow you to correct the unevenness before you attach your final wall covering.

For any electrical outlets in those walls, you will need to pick up box extenders which are available at any hardware store.  They're super easy to install and save a lot of time fidgeting around with moving the electrical boxes.

Rigid insulation and taped joints:

(this is my bathroom job because I forgot to photograph the mudroom.)
For working around windows, you will have to add extra trim and casing but that's not difficult either.


In the case of my mudroom, I wanted a ledge so I only did a 4' wainscot instead of the whole wall.

The mudroom walls were recently insulated, so the R factor in those walls is already higher than in the older part of the house.  The nice thing about the rigid insulation is that it acts as a vapour barrier as well, so you save a step when you use this product over installing traditional fibreglass batts and then 6 mil poly vapour barrier.

I've noticed a big savings already on my winter heating bills and the house stays much cooler in the summer as well!

I hope your fall weather is as glorious as ours has been!


Betty said...

This is an amazing idea and tutorial. I just read parts of this to my husband (who looked at me like I had two heads). Yes, we will be doing this in at least one or more rooms of our old home. Thanks so much!

ANNE said...

You're so welcome! Men do seem to have difficulty thinking outside the box when it comes to construction - lol!

Butterfly 8)(8 Bungalow said...

Wow, Anne it was a a lot of work! But, it looks wonderful and suits your home's style, plus keeps the house warmer and cooler depending on the time of the year. Great idea and great work! xoxo Su

Cynthia said...

Anne, this is why you have earned the name Rock Star, you aren't afraid to take on any projects and if a problem you figure it out


Kathy Moreland said...

Great tips! Love the bead board. You are so innovative! Have a great weekend!

Junkchiccottage said...

This is fabulous Anne. What a great way to insulate and save money. Wonderful tutorial. Happy Week End.

A Joyful Cottage said...

Glad you found a solution that work for you. Looks nice, Anne.

Kim Hood said...

What a great bonus, Anne! Beauty and function. Perfect. You are so blessed to have beautiful fall leaves...gorgeous!

Art and Sand said...

You always amaze me with the projects you tackle and that photo of the fall leaves is amazing.

Magali@TheLittleWhiteHouse said...

You're an amazing DIYer! And I agree insulation is very important in old houses!

monkey said...

anne we have a house built in the 80's and i don't know why but if we have insulation it must be cheap or worn out and our electric bills are outrageous even with us trying to conserve. please may i ask what brand you bought so i can look it up, i am not sure what rigid insulation is... thank you xx

ANNE said...

The trouble with cellulose and fibreglass insulations is that they lose their R factor over time - not completely, but it isn't as good as when first installed. I used extruded polystyrene foam insulation. It comes in either 2'x8' or 4'x8' sheets and has different R factors depending on the thickness. It's also moisture resistant (another factor in how well the fibreglass and cellulose insulations perform, if they get wet, they lose their R values). Dow Corning is the brand I used, they call it Styrofoam Insulation. You can find it at any building supply store. Cheers!

Kimberley Seasideave said...

Amazing blog post Anne!
many people don't give what's inside the walls a second thought.
It was one of the first things we did when we moved into this 1970's home, redo the insulation and it made such a big difference.
Loved your fall photo too!
Have a wonderful week! :)

Down by the sea said...

That is a great idea I have never thought of doing that! Sarah x

Marie Blackburn said...

I was going to ask you if you noticed a difference on your heating bills Anne - that's awesome it's made a big difference. I'm going to keep this tip in mind when we redo our laundry room in a few weeks - thanks!

Jennifer said...

It is smart to consider what's inside your walls as we head into another Canadian winter. We used a similar method to insulate the shed we just built. In this case, we finished the interior walls with a sheet of plywood over the insulation ( it is a shed so less decorative plywood was fine).

Amy Ellis said...

I see you are surrounded by beautiful fall color, it's been so dreary here. Once again, Anne, I will be referring to one of your tips as we proceed with updates in the new place. This is truly one of the best tips I've seen for older homes when people are trying to save energy and make their house more comfortable in both summer and winter!!

Shirley@Housepitality Designs said...

You always come up with the greatest ideas and projects....bookmarking this post for future reference (for the hubby that is!!!).....Thanks ... you are amazing!!!