Adding Additional Insulation To Walls | Do It Yourself

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Should I Add Additional Insulation To My Walls?

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Hi Itchy:

This is a great website. Thank you for all of your helpful tips.

We purchased a home in cold Montana. It was built in the 1970 and it is 2x4 construction. It is a cold house and we had an energy audit done. They suggested putting spray foam insulation into the wall cavities that have R-13 batt insulation. They would put a 2� hole on the outside of every bay and spray the foam in and they say that the foam would compress the batt insulation and the wall cavity would them be filled. Once the foam expanded they would trim it off and plug the hole, they we could just reside over the existing siding. BUT we were thinking we could to the same thing ourselves, but use a blow in cellulose product. Your thoughts please.

Thanks from �Freezing in Montana�

Wow! Has your energy auditor ever done any insulating?

Adding insulation to walls that are insulated, even if only partially are difficult. In reading your question it appears you already have R-13 fiberglas insulation which is what is recommended for 2X4 framing. So, I'm confused in that there will be no room to add any additional insulation.

Now if you have some wall cavities that don't have any insulation that would be different and yes, you could rent an insulation blowing machine and do it yourself using cellulose insulation. In fact I have written an article on my website covering how to blow insulation into walls.

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Experience tells me that if you try to add insulation into walls that are fully insulated already all you will accomplish is making a big mess and wasting your time and money. Without actually seeing your home it's hard to advise you any further but I'm somewhat concerned that a home energy auditor would recommend trying to smash down existing insulation to add foam insulation. By compressing the insulation it loses it's R-value. And, if you're not careful foam insulation could expand and actually pull the sheetrock from the wall.

So, I would recommend in the wall cavities that are already fully insulated with R-13 to leave them alone. If you have areas of exterior walls with no insulation then by all means you could blow insulation into the walls.

Related Tips and Advice:

Adding Blown Insulation To Garage Walls
How To Check Your Walls For Insulation
How To Insulate Walls

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