The article on butyl tape wasn't at energyvanguard.com...it was here http://www.greenbuildingadvisor.com/book/export/html/17758

I think you said you're in SoCal, I live a bit north of you.

I'd said in an earlier post that I bought Hardcast 1402 at Ferguson HVAC suppply. It was $27.50, including tax. Check the website, there are Ferguson HVAC locations all over SoCal. All over California for that matter, and many in other states. I don't know if they prefer to only sell to the trade or not, but I walked in and bought it, no questions asked.

As energy rater la has said, it grips hard and seals tight. No ifs, ands, or buts.

I went to their web site and tried to buy online, but they wanted me to setup an account with them. Also, several web sites sold only cases of this stuff.

It's too late now. Plus, article I mentioned says butyl tape was just as good. It's easy for me to check tape every 6-months and see if it's failing. If it fails, I can go to ferguson or try mastic sealant instead of tape.

Sorry, I thought you were asking a question. There's a question mark in the heading.

This isn't Facebook.

I'm late to the discussion..but...
I'm 100% for hardcast 1402 mastic tape.
strong, excellent quality product.
I find that other tapes fail.and have
never been a fan of Nashua products.

if you have problems finding the hardcast
tape hamconsulting, drop me an email.
I get it a bit cheaper than snidley
and might could help you out.

I'm glad to see you applying what
you've learned to your own home.

it may be that you'd need to go to
the supply house snidley used rather
than shop online. with cash in hand
they often change their mind about
selling the products.

the supply house I used to go to would
sell anything to anyone..need an a/c system?
didn't even need epa card! that was one of the
reasons I switched.
but if you went to their website..create
an account. just different branche's way of
doing business I guess.

so back to your first post...
One of my two 12x24 air returns was open to the crawl space. I bought a half stack rectangular duct vent to cover bottom of plenum at return vent on wall by floor. I used sheet metal screws to fasten it to plenum. I then used Nashua 558CA tape over the screws to seal all areas on inside bottom of plenum.

open return to crawlspace..that's never good!
can you post a picture of this? after work would
be best..but if you have one prior to doing the work
that would be nice. someone might learn that they
have the same or similar situation!

I didn't use mastic sealant, but I did buy a 1/2 gallon tub of master flo air duct mastic sealant. I didn't use it and im going to return it. Unless someone tells me I should apply it over 558CA tape inside plenum.

I don't know the brand of mastic you purchased.
some paint on mastics stay wet & flexible.
(why I stopped using Iron Grip by Hardcast)
others dry hard. I use CCWI-181 these days.
hang on to what you have until we see the pictures.
that will help to decide if painting over the
tape would be worthwhile.

trying to visualize..you did the work from inside the
plenum? or from in the crawlspace?

I read the article @ greenbuildingadvisor also.
glad to see that Hardcast was one of the recommendations.
the whole 181 tape situation causes confusion.
181 duct tape may work for sealing armaflex
on refrigerant lines, or to seal covers of heating
systems..but other than that I don't see that duct
tape should be used in air sealing at all.
but that's just my pov.

best of luck.

I took before pictures with my phone but didn't come out good. I'll see if I can take after pictures tomorrow with regular camera.

I just know that it's way better than before since it doesn't pick up air from crawl space anymore.

Gotta go to new years party...

Here's a picture with my first attempt to fix the inside of the return vent that's on the wall near the hardwood floor.

This picture includes the white painted wood and regular duct tape that I had placed over the wire mesh on the bottom of the return vent. So, there was an open area 12 x 24 to the crawl space.

Also, you see the same wire mesh on the upper left. The regular duct tape wasn't sticking to the wire mesh on the upper left and was coming off within a week.

Here's the after picture. I removed everything I had done previously including the white wood panel.

I first put in a 1" insulation board cut to size at the bottom of the plenum over the wire mesh.

I then cut and placed the half rectangular stack duct over the insulation board and attached it using sheet metal screws every 4 inches.

You can see where I used the Nashua 558CA butyl tape to cover the sheet metal screws that I used every 4 inches to attach the half rectangular stack duct.

Here's where I'm wondering if I should use mastic sealant instead of the tape or use mastic over the tape.

that was a hot mess wasn't it? it makes
you wonder what people were thinking!

nice job using the filler over the opening
to the top left before installing half stack
to cover it.
I'd have done the same thing, bringing
all walls to same level before covering.

what is the material lining the return? is that
metal, sheetrock or what..can't really tell.

can you remove the filter grill to work inside the
return?

anyway...the tape. I'd leave what you have.
but take a credit card or something rigid
to squeegee the tape and get the wrinkles
& bubbles out of it.
then take a small paint brush & apply the
mastic.
first...wipe all the walls of the return off
so that the surfaces are clean.

that stuff on the top left of the return
should be cleaned off. it may have come from
r/a being opened...if not..it will come back.
but while you are working inside the r/a see if
you see any openings and use mastic to seal.

mastic seal corners of r/a & paint over the tape.
make sure that mastic is 'nickel thick' and
that it passes the edges of the tape onto the
walls/floor of the return.
this will keep the tape from lifting off on the
edges of the tape. the mastic will create an
extra covering of sealant.

then look at the wall where the r/a filter grill
is installed. mastic that wall to top, sides
and bottom to r/a.

is this a studded wall with the opening cut for the
filter grill? or single wood without studs?

look at the top of the opening of the filter
grill. if you see exterior of wall, studs
and then walls of r/a..you need to seal this
off also. if not..then replace filter grill.

now see on the filter grill where you
install the filter. that trail of dirt/dust
on the lip for the filter. this is air bypassing
the filter. you can use foam weatherstripping
on the filter framing to make filter fit
tighter.

is that a 1" filter? once you seal the return
& ducts (see..using up that mastic!) you may
want to upgrade to a media filter.
see pic attached.

I think you've done a good job. this
last round of sealing is all that is needed.
now you can diy your friends & family!

Happy New Year.

Thanks for that picture. I didn't know you could add a 4" or 5" media filter at the return grill. I thought it had to go up in the attic attached to the furnace. I'll see if I can find a thick air media filter in my size.

Re: what is the material lining the return?

It's sheet metal, but it has dirt spots stuck to it...probably from years of being open to the crawl space. I vacuumed the inside of the return using a shop vac.

Re: can you remove the filter grill to work inside the return?

I removed the entire grill prior to patching the inside of the return. I used screws to attach new metal to wood frame. Metal sheet is all even around the opening. I used 558CA tape to seal all around the opening and into the outside drywall (like you had in a previous picture).

Re: now see on the filter grill where you install the filter. that trail of dirt/dust on the lip for the filter. this is air bypassing the filter. you can use foam weatherstripping on the filter framing to make filter fit
tighter.

I see that the grill frame has little openings, so I'll seal that too.

By the way, this particular 12x24 return air vent picks up a lot of dust and lint from the hardwood floors.

So, I got some mastic sealing to do and thick media filters to buy.

nice.

hamconsulting..I didn't know you
had a filter at the furnace.
that being the case..
when you replace furnace...that
would be the time to put a rack
for the media filter at the furnace.

I shouldn't assume. ever!
but seeing the 1" filter in the picture
I thought the returns were where the filters
were located.

1" pleated filters are very restrictive.
4" filters let more air flow through them.
for the prefilter @ r/a grill...you might
go with a less restrictive filter. what we
call rockstoppers. blue woven $2.00 filter.

it isn't going to hurt to use the media filters
in the r/a. but it will be more costly.

media filters last longer 6 months on average.
my dealer cost on a case of 5) 4" filters was
$135.

you've sealed the return(s)that will stop
air entering holes/gaps in returns, that with
only the filter at the r/a..would allow dust
to bypass filter to collect on coil.

as it is..your well sealed returns eliminate
this dirt/dust source and air is filtered
before coil.

where are your supply ducts located?
what type ducts are they? flex or hard pipe?
I'm going to help you use up the
rest of that mastic!

I appreciate all the help.

I don't have a filter up by the furnace. I had never seen a filter like the one in the picture you posted. Do these have a special name, so I can buy it online?

I'm attaching a picture of my supply vent. It has a metal lip that wraps around the drywall, so there's no gap to the inside of the wall. This particular one in the picture has a dual opening to the kitchen and dining room. You can see the back of the grill that goes to the kitchen. I'm taking the picture from the dining room (open wall between dining room and kitchen, so no door).

Oh, my metal boots have some type of asbestos insulation that's on the outside of the vent up in the attic. These are from the early 1950s. At least that what I was told.

My ducts in the attic are R-6 insulated flex ducts. Flex ducts are taped to boots with foil tape...and I know what you are going to say! Mastic seal these suckers, but it's too much work for me right now and I'm going to skip this mastic sealing at the boots.

Picture got lost...here it goes

I can't find these filters online.
the website on the filter is www.glassfloss.com
but there isn't any info there.
you'll probably have to order these through
your hvac company.
I order from my supply house & call them 4" media
filters with 1" lip. it is pretty easy to buy
regular media filters online...but they require the
r/a grill that holds the 4" depth rather than
the 1" depth.
the picture I posted is a 4" that retrofits into
regular filter grill.

your picture is a supply grill,
that backs up kitchen to dinning room.
the question is...where is the supply duct
that connects to these two grills?
or is this a transfer for return air?
this is confusing to me!

and no no...I wasn't sending you into the
attic to seal the supply boxes.
I was sending you there to seal the
supply ducts where they take off from
the supply plenum! and to seal plenums
to the equipment.

the good thing about flex..it only leaks at either
end, rather than hard pipe which leaks at every
seam & joint.

I have a method of sealing supply boxes from
inside the house. Snidley started a thread
with my picture of how to do this.
but hold out for the mastic tape to do
this sealing.

best of luck

Kudus to you for identifying the open crawl space wire problem and then doing such a nice job fixing it hamconsulting! Your pre and post repair pictures and description are very helpful, as I have a similar forced air vent set up and have been studying how to improve it's energy function. Thanks to energy rater la too, for all he/she posts here encouraging us to get on this.

While I can't address this project just now, it's on my honey to do list for the near future. I took my first look around in our crawl spaces just recently to see what I'm dealing with. Surprisingly, my cell phone camera worked, abetted by a high intensity portable lamp.

Nice job!

Yeah, big kudos to energy rater...great advice and great details for my project.

I need to get a hold of these 4" media filters with a 1" lip. They would be perfect for me.

Going back to the picture that confused energy rater, the double supply vent for the kitchen/dining room is fed by a new R-6 insulated flex duct. Supply plenum at equipment is new and sealed using foil tape.

Flex duct is taped (using foil tape) to the metal boot that's part of the supply vent. I tried to take another picture from inside this supply vent looking up to the attic, but the picture comes out very dark even with the flash turned on.

I'm going to read the Snidley posts to see what I can learn.

I love media filters. so glad I invested
in them! I recommend them to everyone who
has sealed returns & duct system.

Going back to the picture that confused energy rater, the double supply vent for the kitchen/dining room is fed by a new R-6 insulated flex duct.

so the duct comes to the top of that wall
and blows down wall to exit from supply grill?
sorry...can you explain if it isn't like above?

on a different topic..what
size filters do you use?
and you have one or two r/a?
I can call my supply house with sizes and
get a idea of cost.

and maybe I can talk you into getting
some mastic tape. if you plan to keep
air sealing mastic tape and caulk are
going to be your best buds. LOL!

hamconsulting, I'm always happy to help
someone who gets it and is willing to do
the work to do it right.
besides..work is slow around the holidays.

You are right on target with regards to the double supply vent. I think this might be called a back-to-back grill, but it's definitely a supply vent (not a return).

There's a flex duct in the attic that attaches to the top of the metal boot on this supply vent. The metal duct goes down to about 8 inches from the ceiling. The supply vent then opens on both sides of the wall -- one for the kitchen and another for the dining room. So, there's a back-to-back grill.

I put a new picture, so you can see it up in dining room wall.

In terms of the 4" inch filters with the 1" lip, I have two return vents that take a 12x24x1 filter. However, the 4" air filter with the lip would fit perfectly.

I was looking at these z-line hwr air filters, but I wasn't sure if they were the same as the one you had: http://www.cleartheairinc.com/Honeywell_Merv_11_Furnace_Filter_p/gf-m11-hw-5pack.htm

I'd be willing to buy a couple of filters and a roll of Hardcase 1402 mastic tape. You take PayPal?

However, I need to find a supply house to sell me the filters since these need replacing every year or so.

two things:
where the vent is attached to top plate
should be mastic sealed.(I know..you don't want
to get in the attic @ each supply...but I have
to tell you)
and,
the double supply is called a panned joist/stud bay.
hardly ever see those!
unless there is something blocking off the
stud bay below the supply grills, the supply
air continues down the wall to the sole
plate of the wall. to push the air out
of the supply grills, you'd seal off the
wall opening at the bottom of the supply grill.

this could be a simple as putting a piece
of the metal you used in the return
and mastic sealing it in place. then put
the supply grills back on.
just keep the mastic in the area that the
supply grills cover. too bad you don't have
the hardcast tape. if you use the tape you
have, then mastic over it.

the link you include shows the same filter I
posted a picture of, but doesn't have it listed
in the drop down window.

call them to see if they have it with the 1" lip.
my filter is Z-Line 400 HWR

I put in a call to my supply house to price
the filters there. they don't stock these
filters, they are special order.

Have to leave for a while..gotta work.
but will get back to you with their price.

you wouldn't be purchasing from me, but
from the supply house I use. don't think
they do paypal..but credit cards are ok.
I would pick up and ship to you, as they
don't ship. so all you'd pay me is postage.

we'll talk more when I get back this evening.

was in a bit of a rush, so to clarify.
to do this we would have to go to email
that way I could give you # of supply house.
which you'd verify by looking them up online.
after talking to them, you would call & order
case of filters & mastic tape (hopefully you'll get the
mastic tape!).
I would pick up your pre-paid order.

often my clients pre-pay supply house..and deliver.
just not to your area! the part I come in on is
picking up & mailing to you. case of filters is light,
but bulky. the weight is the hardcast tape.
by email we could exchange price to ship...and
address to mail to you. shopping usps, ups & fed ex
prices we can decide via email.delivering by truck.
18 wheeler is expensive. manager told me that
there was an $80 charge for mini split covers.
these were small, so a high price for a small pkg
makes other options more attractive.

it is only a few times that I've done this.
but when you see someone trying to do it right..
it is worth it, in time & hvac supply access, to me.

as you'll find out by clicking on my user name
to access my email, the 'not so secret' will be
out. once again.
not many men with my name!

did you have a chance to see if the double
supply chase stops at the bottom of the grill?
do you understand what I mean?

with the chase stops at the supply grill..
then the velocity of the air is greater & not
lessened/wasted continuing down the wall.
this will give the supply grills more
air.

sorry to have taken longer to clarify than
usual. I'd been keeping a close eye on this thread,
but had some paying work to do.

take care.