the things you learn when you play around with your blower door! LOL!
the things you learn when you play around with your blower door! LOL!
to add to energy _rater_La's position,
Nothing is as convincing as seeing the leaks. Numbers are cool but seeing stuff blowing in the breeze really drive home the issue. Wherever you see insulation being blown away during the pressurization test, just see dollar bills and comfort blowing out of the house. Now, which are you going to focus on: the small leaks that are within easy access or the open barn doors that invariably seem to be more difficult to get to? Plan on making reliable access including 3/4" plywood catwalks screwed into the tops of joists so they don't flip and dump you through the ceiling or hurt you. Do what you gotta do to clear away the cotton candy to get at the work area to do it right. Once it's all sealed, fire up the fan and check it from the attic again before covering up with insulation. Here's where a smoke source can be very illustrative. What leaks under pressure may not leak under vacuum and vice-verse hence test both ways. While TiCl4 is the best stuff I've ever used to show minute air movements, you can get an inexpensive smoke puffer on the web that uses model railroad locomotive smoke generator fluid so its safer.
Remember to check over all the interior walls looking for air bypasses and missing top plates as these can be huge losses. Plumbing and electrical penetrations into the attic along with combustion venting rank pretty high, too. For those wanting to seal around chimneys and vents, be careful. The code requires stated clearances to combustibles on masonry chimneys with sheetmetal firestopping that can be caulked to a masonry chimney but all factory built chimneys and vents can only be caulked if their listed instructions allow it. Some systems, esp. air cooled woodburning fireplace chimneys can NOT be caulked at firestops and to do so may actually cause the chase to overheat and could lead to fire.
Having that Duct Blaster is a golden opportunity so take full advantage. Who knows, you may locate disconnected ducts you never could otherwise even when the blower door numbers showed a leak "somewhere".
Side note: back to my fireplace chase: there should be "fireblocking" above the fireplace at the ceiling level per the code. This can be any number of materials listed in the 2009 IRC R302.11 or otherwise approved by your AHJ. For me, either 3/4" plywood or 26 ga. galv. sheetmetal are the more common materials for overhead but T-ply can be used if approved by the AHJ. It just has to provide "an effective barrier" to slow fire' spread and contain much of the smoke. Since the area above a fireplace in a dogshed is technically an "attic", treat it as such. This means air sealing and insulation but being so small, these areas seldom require ventilation. I've never seen ill effects from not ventilating these micro-attics but I have seen cold air issues from ventilating them. I've never seen shingle failures from non-ventilated dogshed attics. If you're really worried about venting this area, you may consider something such as this: http://www.roof-2-wall.com/
One last note on attics and HVAC equipment: The code prescribes minimum access size, which most attic pull down stairs barely meet but many of these stairs are not rated for the load of one man, let alone carrying heavy equipment. Before using wooden stairs, take a wrench and tighten the truss rods and bolts so you don't take a nasty spill. There must be a solid stable landing place where you enter the attic. When equipment is located up there, there must be a light switch located within reach of the stairs and there must be a grounded 125 vac outlet within 25 feet of the equipment. There must be solid catwalks 24" wide and the equipment must be within 25 ft unobstructed walkway unless the catwalks are 30" wide and adequate lighting along the way. Don't forget safety. How are you going to rescue a worker disabled when he's wedged in the attic out near the eave in a low pitched roof with 2x4 trusses and no catwalks out to him?
We can talk about weatherizing pull down stairs vs. replacement choices later. Fun stuff!
@ hearthman too bad we can't do a project together...it would be so much fun!
Ugh!!! 108CFM@50Pa Great! But not the smoking gun I was looking for. He said their company has sealed system's to get to numbers like mine. I was up in the attic with the rep and we were feeling collars, almost nothing was leaking from the collars. One or two you could feel, but barely! No moving fiberglass, nothing!
The company was great, the guy was really nice and tried to look for anything else obvious. He couldn't see anything that stood out. He had some decent suggestions, try keeping the basement door open to move the pressure plane down. But other than that I'm really at a loss now.
I'm going to go back into the attic this weekend to look for more black fiberglass... It has to be there!
Taverty, in your #17 post you mentioned noticing air coming from your downdraft vent when the wind had started to pick up. You also made mention that you noticed drafts blowing through the electrical sockets in the outside walls; where are those electrical sockets located? First, second floor? Does it blow through sockets located on all the outside walls, or just one side of the house?
Was that a bathroom exhaust vent I saw in the video? Did you check that for draft? Lastly, what is that, looks like pvc pipe, in the attic video-you can see it at the 5:09 mark in the video. Looks like it has some kind of orb shaped thing in the middle of it.
hearthman, 50Pa is what the tech said. I knew it was trouble when the display read "LO" and he kept having to add collars to the fan. He didn't have a fog machine or IR Camera and he didn't seem to be calculating anything. What is the subtraction method?
tipsrfine, when the wind picks up, we definitely get more air coming through the downdraft and fireplace. But even on a dead calm cold night there is a steady stream of air coming in. The really drafty electrical sockets are on the back and left side of the house on the first floor. The absolute worst one is on the wall to the right of the kitchen bump out. Even the outlets in the bump out aren't as drafty as this outlet. It's interesting the outlets on the front of the house have no perceivable draft, right ride ever so slight. Rear and left side, you can feel it.
I haven't fully checked my bathroom exhaust vents. Before I sealed them with caulk and foam I only checked to make sure the little plastic backdraft damper was opening and closing correctly. I'll double check for any leakage this evening.
That PVC pipe is my radon pipe, the orb is my radon fan. I had a slightly elevated Radon level and that fan runs 24/7 to depressurize under my basement slab so the radon goes out that pipe instead of into my living space.
Well, this is a challenging one.
You've done everything right and got all the data needed that should produce some answers but back to square one.
All the symptoms and high bills all lead to a house that leaks like crazy but the blower door-test says otherwise. I can't help but wonder if the gauge may not have been set right or something was wrong with that test. Were all the doors in the house [interior] open? Basement included in conditioned space and Volume? Were you able to walk around and observe leaky areas during the test?
I'm really guessing here but the facts just don't add up. If you haven't already I would suggest a follow up call with the original auditor to update them on the situation. If it were me I would want to know what was going on and run another test. I suspect they may plus it would be helpful to see what if any changes have occurred after improvements.
I forgot to ask, can you inspect that radon system piping to make sure it is all intact and not depressurizing the house?
had you done any duct sealing between the blower door testing & today's duct blaster test?
I know you did some house leakage sealing.
even small leaks on duct system adds up. what size is the central system in your home?
and sealing the bath fans...re-visit my post on gardenweb about dropping the
cover of the bath fan and sealing the gap from inside the house with hardcast 1402
mastic tape. foam shrinks and doesn't seal as well as you think. caulk doesn't fill large
gaps & as it dries it shrinks, so if you caulked...you may need to touch it up. if you foamed
then caulk foam to sheetrock/housing of bath fan. or just mastic tape it.
I've been thinking about your bumpouts. if the building envelope was compromised
when they built these bumpouts, it will be both at the bottom of the bump out
and the top. they wouldn't have changed methods.
while opening up the cabinet bumpout is the best way to air seal it, I usually seal
from exterior and follow up with interior sealing.a secondary seal is always a good idea.
its difficult to fit a caulk gun into the
cabinet, but if you can...caulk all the joints in the wood. if you have a sink, move the
escustion and seal oversized holes there. I found a product at hvac supply that is a rope
caulk called Thumb Gum. it is a pliable material that you can use around plumbing penetrations.
I've used it with good results.
I have some cabinets with false boxing above them. I sealed from in the attic, caulked false
boxing joints & tried to caulk inside cabinets...no luck...caulk gun too big/cabinets too small.
I used hardcast mastic tape to seal the gaps. doesn't look great, but it is just storage for
all the building science books & related materials. sealed well.
just ideas on how to seal these areas for you to think about.
did you feel around return framing at attic floor? 2x framing, corners & where they rest
on each other?
what is sq ft of home & what were blower door numbers ? (not ela but 2500 cfm at 50pa
number) if you've posted this already...sorry I must have missed it.
have you been in contact with your auditor since the test?
From one of the first posts,
CFMs @ 50: 2400
Airflow building: 231.84
Airflow people: 75
BAS at CFMnat: 231.84
BAS at CFM50: 3987.64
70% of BAS: 6
Volumes needed: 8.40
I ran the numbers to convert to ACHn and came up with something like .24 but was guessing on N factor. Still close enough for me to question it. He also has a low RH so am really thinking those numbers may be wrong.
I'm questioning a lot more than just the numbers but the auditor's technique as well. Several things questionable here.
Thinking about the cold air infiltration from outlets near but not 'in' the bump out leaves me to believe there is air shunting laterally through walls. You can get air into one stud cavity then travel sideways through holes bored for wiring and pipes (which shouldn't be in exterior walls-wires ok). A lot questionable here.
I think for one they got the wrong company to do this and two, they need someone with an IR camera and some sort of smoke puffer or fog machine to find these leaks.
The duct blasting tech noted that since we have 9' ceilings on all three floors he thought that could be a contributing factor in raising our neutral pressure plane. He said in other homes the neutral pressure plan is probably even with the first floor, but in our house he thought it was mid way up our first floor. He said this would cause the negative draft at the downdraft and fireplace since they are both lower than the pressure plane.
Also, since the duct blaster tech was surprised to hear this I thought it may help here. My home doesn't have any house wrap, no TyVek, just brick veneer front with vinyl siding on the other three side, then under that OSB.
I don't know if it matters, but our house is actually 5,000 sqfeet. I mentioned it to the audit company but she said it just needed to be a rough estimate. I'm mentioning it now since I'm grabbing at anything!
During the blower door test it really seemed like the house was struggling for air (maybe that's how every house feels). It felt like you were in a vacuum and any door you opened to the outside you were met with a major gust! Also, my Trane propane furnace in the basement shut itself down during the test. I can only assume it was because it detected a major downdraft on the flue. The blower door tech was surprised it did that. We didn't cut the power to it before the test, we only turned it off at the thermostat. She almost stopped the test right there once she saw that. When the test ended I had to cycle the breaker for the furnace to power back up.
stvc, I'm going to have the original audit company out to do the test out. I was originally going to wait until I had the attic insulated and rim joist spray foamed but I think it may be useful to have her out now to verify the leaks I did seal. The active radon system (the orb part) was installed within the last year. I didn't notice any change from before and after it was installed. The PVC pipe has always been there, passive radon pipes are required here. I will still double check it. I can unplug it in the attic very easily. However, I'm not sure how I can check the PVC pipe itself (buried in interior walls). I assume I'd have marks from water on my walls if there were any breaks. Also what is the N factor? Is this something I can ping my auditor on and get an accurate value?
energy_rater_la, I definitely plan on following all of your sealing advice from GardenWeb. It's my easter weekend project, much to my wife's chagrin! Yeah, I have to seal all the pipe penetrations under the kitchen sink, which does sit in the bump out. I'll try the Tumb Gum, if there's one thing I've learned it's that I really dislike expanding foam!! I haven't really been in contact with my auditor since. She offers a test out, which I was going to take advantage of, I really wanted to do it at the very end. But at this point I should have her out again. My downstairs unit is a 3.5 ton A/C 100BTU furnace (80% efficient). My upstairs is a 2.5 ton heat pump, not sure of the electric coil BTUs. When they come on though it's nice and toasty, but all I see is dollar signs!!!