Insulation behind shower walls?

[Itsjustdirt]

Working in a 1950s house, in warm Southern California, that has no insulation. Redoing the shower (which had no insulation) with hardi, Redgard, and ceramic subway tile. I usually throw unfaced fiberglass insulation between the hardi and the exterior facing wall, nothing on interior sides.

The contractor pulled it out and said he'd rather leave it uninsulated because "none of the house has insulation and insulation behind showers can cause mold issues, no need to risk it here if the there's no insulation in the rest of the house".

Location- Socal - warm weather, few rainy days a year.

Will this cause an issue later? What's the "right" way here?

 

[larry4406]

I'm in a different climate than you (northern VA) but here we install unfaced insulation on exterior walls of showers followed by concrete board, Redgard or similar, then tile.

 

[DieselNut88]

I always install insulation on all interior walls for sound deadening. I just did a shower and installed unfaced fiberglass. You could also use roxul.

 

[kngelv]

Definitely put insulation in. Makes it quieter in the shower and the house.

James

 

[DC73]

The contractor pulled it out and said he'd rather leave it uninsulated because "none of the house has insulation and insulation behind showers can cause mold issues, no need to risk it here if the there's no insulation in the rest of the house".

Contractor is wrong. Insulation will not cause mold issues. Water and/or water vapor intrusion into wall cavities can cause mold issues. The contractors responsibility is to make the walls air and water tight while allowing the walls to breathe to one side or the other to allow water vapor to escape.

DC

 

[acer66]

Contractor is wrong. Insulation will not cause mold issues. Water and/or water vapor intrusion into wall cavities can cause mold issues. The contractors responsibility is to make the walls air and water tight while allowing the walls to breathe to one side or the other to allow water vapor to escape.

DC

This.

 

[Red 17]

While you're at it, consider blocking for shower grab bars if appropriate.

Serving suggestion.

 

[Itsjustdirt]

Blocking is done, good suggestion though.


SO..... Will this CAUSE A PROBLEM without there being insulation? I know its not ideal, but will the lack of insulation cause condensation issues or anything?

Thanks guys!

 

[ddawg16]

It's a good question.

If you have insulation, and a water leak, the insulation will make things worse because it will absorb moisture.

Key point here....."Water Leak".

You can have 2 points of view....

1. Water Leaks will eventually happen

2. Water leaks are not allowed

I'm of the "Water leaks are not allowed" camp.

I also have a 50's house. I have insulation in the walls....now. Yeah, non of them were insulated.

I hope you have felt (tar) paper behind that HardiBacker?

HardiBacker is NOT water proof. It should be Tar Paper, Hardi, RedGuard, Tile, Grout sealer.

I added 2 bathrooms to my 50's house.....I did hot mop on both of them. Everyone raves about Kerdi.....but....does it have 70 years of service?

 

[Lassen Forge]

They didn't put insulation behind our shower walls, and in the winter I hit the walls with hot water before I get in. Otherwise... B-r-r-r-r!!!!

One of the things I want to correct when we redo the bathroom!!!

 

[Itsjustdirt]

HardiBacker is NOT water proof. It should be Tar Paper, Hardi, RedGuard, Tile, Grout sealer.


Thanks for the reply! One thing is incorrect about your order though... no tar paper and red guard on the same walls. You just made a moisture sandwich sir.

 

[Bretny]

Insulation dosnt just help when your trying to heat a space. It also helps when trying to cool and dehumidify

 

[GMCGarage]

Working in a 1950s house, in warm Southern California, that has no insulation. Redoing the shower (which had no insulation) with hardi, Redgard, and ceramic subway tile. I usually throw unfaced fiberglass insulation between the hardi and the exterior facing wall, nothing on interior sides.

The contractor pulled it out and said he'd rather leave it uninsulated because "none of the house has insulation and insulation behind showers can cause mold issues, no need to risk it here if the there's no insulation in the rest of the house".

Location- Socal - warm weather, few rainy days a year.

Will this cause an issue later? What's the "right" way here?

Ask him why he is building a shower that gets water behind it??

Noise reduction is the best reason for it.

 

[Falcon67]

That would make the back shower wall in our master cold as hell in the winter. I put kraft faced into the stud bays when we re-did it this spring. Contractor use backer board, sealed the seams and used a rubber base that came up the walls. Plus the tile and grout are sealed (two coats). So no - there should not be any water getting behind the tile. And if it does, it's got a ways to go to get to any insulation.

 

[bdbecker]

This must have been common thinking during that era, even in Iowa. My house was built in 1960 there was no insulation in the walls around the tub/shower area when we opened it up to remodel. One of the walls is an exterior wall, the other wall is exposed to the attic midway up (split level house). I did insulate and Wife no longer has to warm up the bath water during the winter months. The risk of water is probably much lower nowadays as technology and techniques have advanced.

 

[rustyjames]

I'm pretty sure from what I've read on the John Bridge site if you're using Redguard, or other water barriers on the tile backer, don't use anything behind the backer board.

 

[rayra]

Contractor is wrong. Insulation will not cause mold issues. Water and/or water vapor intrusion into wall cavities can cause mold issues. The contractors responsibility is to make the walls air and water tight while allowing the walls to breathe to one side or the other to allow water vapor to escape.

DC

This.

I also fill the interior walls in for sound, any time I open bathroom walls.

 

[ddawg16]

HardiBacker is NOT water proof. It should be Tar Paper, Hardi, RedGuard, Tile, Grout sealer.


Thanks for the reply! One thing is incorrect about your order though... no tar paper and red guard on the same walls. You just made a moisture sandwich sir.

If Red Guard is so good? Then how would any moisture get to the hardibacker?

 

[davo727]

Well im using concrete board,,,, and all three walls of this shower are interior walls. houston area. Put insulation just for sound , or nothing ?

 

[Itsjustdirt]

If Red Guard is so good? Then how would any moisture get to the hardibacker?

I’ll ask you the same question... if Redgard is so good, why use tar paper (that will trap water IF a little gets by the Redgard.

Or, why use the Redgard if your tar paper works so well.