To insulate or not to insulate?

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Posted by: from Toronto
7/29/2012 at 9:15:59 PM

My house was built in the 50" at the time of latt and plaster. The main floor bathroom (4 piece) is not insulated. I asked if the workers are going to insulate and they told me it would not make any difference as the whole wall would need to be done. Which is not an option at this time, so no, they are not going to do it.

Nor have they insulated the interior walls for sound reduction. it's a bathroom for goodness sake, right across the hall from someone's bedroom and very near to the living room.

This doesn't make any sense to me. (My dad a very handy man, would and did at every opportunity shove insulation into every crease he could find and that drafty house we lived in, was eventually quite warm.)

Am I wrong in my thinking?

Thank you for your replies

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Roland from P.F. Eternity in Cambridge
Date/Time7/29/2012 at 10:25:45 PM

No, I don't believe you are wrong in your thinking.

In my opinion there is no good reason for those walls that are going to be opened not to be insulated. My thoughts are that the interior walls should have Roxul safe and sound and the exterior walls should be insulated with Roxul insulation and a vapour barrier over that then the walls closed in.

Every bit can make a differents and starting somewhere is the beginning of completing the insulation of the exterior walls. Getting it right, making it right and doing it right.

I hope this helps.

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Jeff from Newson Interiors in Dunrobin
Date/Time7/29/2012 at 10:52:14 PM


Not knowing the extent of the work being done in your bathroom makes a reply difficult. I'm assuming that a portion of the lath and plaster walls were removed from an exterior wall.

I agree that they should be insulated prior to closing up the walls. Yes the entire wall should be done, but if that isn't in the cards right now, so be it. It would be a waste of material and labour not to insulate now because when you do get to insulate, the new drywall and finishes will have to be removed to do it. Doing it right the first time is always less expensive in the long run.

I laso agree that insulating a bathroom for sound is a good idea, although not necessary, the walls are open now so why not? If this wasn't specified in the contract, have it added. It will probably be at an additional cost but well worth it. If you do get them to insulate, ensure that a 6mil poly vapour barrier is installed as well.

Remember, you are the boss, if you want insulation then get insulation.

Hope this helps.


Newson Interiors,

Ottawa ON

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Scott from Canadiana Kitchens in Barrie
Date/Time7/29/2012 at 11:09:38 PM

Hello Sheila

No you are not wrong with your idea that insulation is a good thing especially behind a tub. The contractor is also corect in that the rest of the house is not insulated but if you do not insulate behind the renovation you are doing now and you renovate the rest of of the house later are you going to rip down the bath walls to insulate latter? So yes it is always a good idea to insulate and vapour barrier!

The work that is to be completed should be in your contract that your contractor provides to you before work is started.

Scott Hunter

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Date/Time7/30/2012 at 9:32:36 AM


You are correct. Every little bit helps both with the temperature control and the sound proofing. The previous comments state the rationale and I too suggest the Roxul Safe and Sound, a good product.


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Date/Time7/30/2012 at 9:39:05 AM

If you can insulate, you should insulate. Period.

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Date/Time7/30/2012 at 11:03:21 PM

You are not wrong in your thinking.

As a professional renovator and a past chair of the Toronto, Ontario and Canadian Renovation Council.

I am a firm believer, like your dad, that whenever there is an opportunity to insulate and install a vapour barrier prior to the installation of drywall then you should take every precaution and all the steps to do so. My concern is if they have not insulated properly then are there other problems in their renovation work like having the plumbing butting up to a cold wall or is the electrical installed without GFI's. If short cuts are taken with the insulation then it worries me that there could be other shortcuts taken.

It is the most responsible thing to do in saving energy usage and costs and helping with the enviroment. Although it is a minor area compared to the rest of your home it is at least the start of having a more effective and insulated home as it may be a bathroom today but it could lead to a larger renovation in the future. It could also give you a better resale value.

Unfortunately there are too many trades/renovators/contractors that do not conform or price the projects accordingly or even to the Ontario Building Code (OBC). Also there are homeowners who only want the cheapest price possible. In such cases the renovators/contractors/trades will price or renovate not as per the OBC but only to secure or win the "project". I guess it is a matter of ethics.

Lou Frustaglio


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Date/Time8/21/2012 at 9:14:53 AM


This is a little late for you because the work has already progressed, but perhaps this will help others.

My concern is basic to the renovation of the bathroom. If the room was plaster and lathe, did the renovator only knock down the plaster and not gut the bathroom. The cost difference is minimal, and the long term benefits far outweigh any additional costs. There is no way of knowing what is actually going on behind a wall unless it can be seen entirely.

Insulation of interior walls may not be necessary, However, this is Your home and Your choice.

Had the bathroom been gutted, insulating or sound proofing wouldn't have created a "not an option at this time" situation. Cutting corners and patch work is never a good idea, in my opinion, especially when it comes to wet areas like bathrooms.

Always remember this is your home, your money and potentially your family's safety at risk. There is no right way to do the wrong thing.


Trinity Renovations

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