Priority - Insulation and bathroom exhaust vent system (ceiling through roof)?

2/26/2012 at 1:28:15 PM

Hi Tanya

Wise move in upgrading your attic insulation & installing bathroom ceiling fans!

There is no firm right and wrong way in the order that the installation needs to be carried out.

However if the new blown in Cellulose is installed first and the ceiling fan after the fact, there is a chance that the loose insulation is going to fall in to the bathrooms. Not only is this messy, you loose the insulation in the attic.

I am assuming the guy that told you this was the ceiling fan contractor, maybe he does not want to get covered in loose fill insulation!!

In my view this is how I would undertake this contract, especially as you are removing the existing insulation:

1. Remove existing attic insulation, especially if it is old loose fill. You can get it pumped out, most insulation contractors in our area provide this as a service.

2. Install Roof vents in shingled roof.

3. Install Bathroom ceiling fans in bathroom, ensuring a qualified Electrician wire them in.

4. Connect Exhaust duct from ceiling fan to roof vent in attic, ensuring that any joints in the duct are sealed and the entire length of duct is insulated.

5. Install new cellulose loose fill insulation.

The job if coordinated properly with all the sub-trades should not take more that 2-3 days.

Hope my input helps, please feel free to contact me if you have any further questions.

Kind regards

Julian Evans

2/26/2012 at 10:13:05 PM

Hi Tanya, I noticed in your previous post that you have a flat roof. You may have to route the exhaust fan ducting through the ceiling joists to an outside wall to avoid going through the roof and causing potential problems. If this would mean too much damage to the ceilings along the route to create access, you may need to mount the fan into a wall and run the ducting along a the edge of the ceiling to an outside wall and create a bulkhead to cover it. Most fans can be installed vertically or horizontally with no problems. This would also eliminate any concern of when the insulation is installed.

I agree with Julian that the duct should be on the warm side of (under) the insulation and should still have its own insulation, even if it is in a bulkhead.

You should be aware that R50 of blown in cellulose is going to be about 18" deep.

Good Luck with it!

Jim Kuzma

Kettleby Handyman Services

2/27/2012 at 12:29:51 AM

Hi Tanya,

So if I understand your question , you want to know if you can install some bathroom fans without doing a new roof and cutting in roof vents at the same time? Well, the amount of work and trouble will depend on the type of roofing you currantly have.

I will assume that you have ashphalt shingles. if you do, and if they are not TO old and brittle (15 yrs and older) a good roofer should be able to remove the shingles on the area of the roof where you want to instal the vent flashings. He would then replace the roof shingles, cutting them to accomodate the new vent housings.

You then have to insulate the vent pipes that run from your extractor fan housing to the vent housing and flashings .There is an insulation you can buy that is designed for this purpose.It is a role of insulation that has a foil backing on it, and you wrap this around the vent pipe.

This is important because otherwise you will get condensation in your vent pipe and water will drip back through your extractor fan housing! Not good!!

As an alternative you can vent the warm air through the soffit! You have to instal a vent housing designed for this puropse, and you should have a solid vent installed for 4' either side of the venting housing.

Long story short, if you or your man ain't handy, a competant contracter will save you a lot of stress !!

2/27/2012 at 4:01:58 PM

To specifically answer your question, it is best to install the exhaust fan prior to upgrading your insulation for a number of reasons:

1) the ceiling has to be cut in order to install the fan. Doing this before will not only prevent alot of new insulation falling through the hole but save time by not having to return to the attic to top it up.

2) if you wait to install the ducting after the insulation is blown in, you will tramp down the new insulation and have to top it up. Again, this saves time and money.

As per the other postings there are a number of key best practices:

1) insulate your ducts to prevent condensation

2) direct vent to the outside (a roof or wall is always prefered over a soffit).

3) ensure the fan housing is sealed against any air/moisture movement from the room into the attic

Regards,

KIngsway Construction Inc

Glenn Rosborough

2/27/2012 at 10:38:35 PM

Hello

Thanks for the replies!

Hi Julian,

"fan contractor, maybe he does not want to get covered in loose fill insulation!!"

I was told by the energy auditor, the insulation companies.

Hi Jim,

Hi Tanya, I noticed in your previous post that you have a flat roof.

Yes a flat roof

Someone mentioned a snorkel roof vent for a flat roof.

Would an inline fan be better suited for venting through the wall?

I agree with Julian that the duct should be on the warm side of (under) the insulation and should still have its own insulation"

You should be aware that R50 of blown in cellulose is going to be about 18" deep.

I thought cellulose is safer than fiberglass.

Is the depth for fiberglass less than cellulose?

Good Luck with it!

Jim Kuzma

Hi Hamish,

I will assume that you have ashphalt shingles.

I don't know what material was used: It was done 2006. (Double membrane)

You then have to insulate the vent pipes that run from your extractor fan housing to the vent housing and flashings .There is an insulation you can buy that is designed for this purpose.It is a role of insulation that has a foil backing on it, and you wrap this around the vent pipe.

This is important because otherwise you will get condensation in your vent pipe and water will drip back through your extractor fan housing! Not good!!

Good to know!

"a competant contracter will save you a lot of stress !!

I'd never try this!

Thanks!

Hi Glenn,

"It is best to install the exhaust fan prior to upgrading your insulation for a number of reasons:

1) the ceiling has to be cut in order to install the fan. Doing this before will not only prevent alot of new insulation falling through the hole but save time by not having to return to the attic to top it up.

2) if you wait to install the ducting after the insulation is blown in, you will tramp down the new insulation and have to top it up. Again, this saves time and money.

1) insulate your ducts to prevent condensation

2) direct vent to the outside (a roof or wall is always prefered over a soffit).

3) ensure the fan housing is sealed against any air/moisture movement from the room into the attic"

I really appreciate everyone's help very much!

I did not know anything about this type of project but I'm really learning thanks to everyone's knowledge!, patience and ability to clarify things!

2/28/2012 at 1:00:00 PM

Hi Tanya

I am unsure why the Energy auditor has instructed you of this procedure!

It is still my view that the ceiling fan and all it's components should be installed prior to the new insulation.

As you have a flat roof, it is highly possible that you have a Bitumen based torch on membrane, if this is the case then it is highly recommended that a torch on patch is installed over the roof vent flashing to create a seal by a reputable roofing company, if it s decided that the vent has to exhaust out the roof.

Hope this helps a little more!

Kind regards

Julian Evans