Replies

1. 
   bambam | Jan 17, 2007 08:19am | #1

   You should be able to slice it down the middle and carefully remove it and still leave the fascia intact.

   Why do you want to change to unvented soffit?

1. 
   CleanCut | Jan 17, 2007 03:05pm | #3

   Good question. The customer built a 7500 sq ft house with geothermal heat, high efficiency everything, etc. His heating month utility bills are equalling his anticipated annual heating bill total. We looked at his house "thermally" using an infrared camera, and could see cold ceilings all along the windward side of the house. This is a 1 1/2 story house with an inaccessible attic above the kitchen/dining rooms. (Normally these spaces require attic access but he built where there was no inspection so some code requirements weren't met.) I suspect these spaces were insulated with faced fiberglass bats. I haven't pulled a can light/speaker to check for sure what the insulation material is, but it's not working because the vented soffit is allowing the space to become pressurized with 8 degree air. (We've got our first really cold snap going.) As I understand it, fiberglass insulation does not stop air movement very well (think furnace filter). Our solution is to replace the vented soffit with solid, and face the truss heals with an air barrier of xps foam sheets. Sealing all air leakage should allow the fiberglass to work a little better.
   What do you think?
   CC

1. 
   bambam | Jan 17, 2007 04:28pm | #5

   Years ago I worked for a "high profile" contractor, and if your house was in  Texas I would say it was one he built.

   He would frame everything before he put any foil on the wall. Then the foil butted tight under the soffit. When I asked why  he said that they didnt make it for 9' walls and he used let in bracing anyway so what did it matter. All the air from the soffit would into the wall too. Most of his houses are 1/2 story.

   Sigh, he had a waiting list of people to build houses for and is syill building today.

2. 
   bambam | Jan 17, 2007 04:42pm | #6

   Sealing all air leakage should allow the fiberglass to work a little better.

   in your case, yes I think it would help a lot. With your inaccessable attic space it  probably isnt getting much ventilation anyway. I dont understand why someone would spend the money on geothermal and not properly insulate. You might even consider to blow some cellulose before you close it off as long as you can do it without covering up your can lights.

   By all means, if possible, find someone with a blower door to run a test and find other leaks. Chances are if you seal that one, another one that you have now that you may not notice will be more noticeable.

    

1. 
   CleanCut | Jan 18, 2007 04:23am | #9

   We ran a blower door test at the same time as the IR camera. We decided the biggest bang for the buck was replacing the vented soffit and sealing the truss heals. Incidentally, during the blower door test you could feel fresh cold air rushing in through the sliding door cavity in the master bedroom.
   To give an idea of how much fresh air is coming in to this house, they have 5 gallon humidifiers running in all 4 bedrooms all day long. They can't get their indoor humidity above 20%, the wood floors are opening up and their miters are opening.
   CC

1. 
   bambam | Jan 18, 2007 04:35am | #10

   Sounds like you got an OP reading or close to it. Without looking at it I say you are on the right track.

   btw if you need a grinder thats lightweight you might try a Rotozip with a grinder attachment. I bought mine because it has a 1/4" collet for router bits, and I use it to mortise doors with. I never thought I ever need the grinder but I use it more than I thought I would. Its very easy on the arm for overhead work.

3. 
   BillHartmann | Jan 18, 2007 05:12am | #11

   "The customer built a 7500 sq ft house with geothermal heat, high efficiency everything, etc. His heating month utility bills are equalling his anticipated annual heating bill total."In addition to the other problems I want is there is some drastic problems with the geothrmal/heatpump system.The reason that I ask is that is should have been sized to meet the needs of the house as constructed an not the as screwed up.If it was then it should not be able to run long enough to generate 12 times the bills..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

1. 
   CleanCut | Jan 18, 2007 03:40pm | #13

   The homeowner contacted the heat pump installer first. He said his equipment is running properly. But that wouldn't really answer your supposition, would it? Could you explain?
   CC

1. 
   BillHartmann | Jan 19, 2007 08:17am | #14

   HVAC equipment is designed to match the load of the structure. For cooling it should run 100% of the time at the upper design tempature.For heating there would be some more capacity, but still operate a large percent of time.So the building has been using 12 times the heating capacity that the was expected.Unless all of the "winter" weather has been mild I don't see how the HVAC could keep up. It would have to be grossly oversized..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

2. 
   CleanCut | Jan 19, 2007 03:23pm | #15

   It has been mild up to mid January. (40s and 50s) Now that we're below zero in the morning I doubt it does keep up. No matter how efficient the equipment is it can't raise the temp in the back yard 1 degree (an exaggerated example of what the HVAC is being asked to do).
   I think they were expecting heat bills in a certain range for the 6 months of heating, and they are seeing the 6 month total come up on their monthly heating bill. So it's a 1 to 6 ratio.
   I don't know if this helps.
   I have heard that many HVAC installers design on a worst case scenerio so equipment ends up grossly oversized. Maybe that's what happened here.
   Is there an HVAC for dummies book? Somewhere I could learn at least enough to speak in the right terminology?
   Ben

3. 
   BillHartmann | Jan 19, 2007 04:39pm | #16

   I don't know of any such book.There might be something in the Owner Builder forums.JLC has had some articles in the past that fall into that area.You could look them up at http://www.jlconline.com then Research..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

4. 
   alanj | Jan 22, 2007 12:22am | #21

   It is not really possible to have too much soffit ventilation in a heating climate.Your problem is with improper sealing between the heated areas and the vented, i.e. unheated attic.Your infra-red photograophy show heat excaping to the attic as the wind creates a vacuum drawing the moist heated air up through what is an improperly installed vapour/air barrier.Depending on how cold your climate is, that moisture will freeze and/or condense when it meets its "dew-point" in the attic. I would suspect, depending on your climate, that you will have water pouring from your ceiling fixtures come spring (frigid) or mold and merely wet insulation above (moderate climate,).Solution...try and seal it up. Caulks and foam seals where applicable. will help. Aluminum paint as aprimer is better than nothing and in combination with the above will apparently work

5. 
   RichBeckman | Jan 20, 2007 06:55am | #17

   "I have heard that many HVAC installers design on a worst case scenerio so equipment ends up grossly oversized."And I've heard that many HVAC installers really don't understand how to size a unit properly (or are too lazy to do so) and use a simple process that guarantees the unit won't be too small (but almost always oversizes the unit).Rich BeckmanThis signature line intentionally left blank.

2. 
   Stilletto | Jan 17, 2007 01:54pm | #2

   Run a grinder with a metal cutting wheel down the middle of the pieces,  parrallel to the outside wall.   This will cut the soffit in 2 pieces,  then you should be able to pull it out in two pieces. 

   Cut your new ones at the length from the wall to the inside lip of the facia,  slide them in and center them,  because they are an inch short of the outside of the subfacia. 

   Buy a Malco trim nailer (about $10),  it holds stainless steel trim nails while you drive them in.  Be sure to use stainless thy don't bend as easy as the aluminum ones. 

    

    

    

   
   

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   Edited 1/17/2007 5:55 am ET by Stilletto

1. 
   CleanCut | Jan 17, 2007 03:09pm | #4

   I knew you guys would come up with something. A grinder! Great idea. I was envisioning holding my circular saw upside down for 200'.
   Thanks for the help.CC

1. 
   Stilletto | Jan 18, 2007 01:47am | #7

   I made a handle for my 6" grinder that makes it kind of like a circular saw without the table.  Works great for cutting vinyl siding and soffitt.  

    

2. 
   shelternerd | Jan 18, 2007 05:25am | #12

   We have an electric sheetmetal nibbler made by Kett. It's a three bladed slitter powered by an electric drill that removes a curly 1/4" strip from the panel. No dust, easy clean-up. we use it for making copper countertops as it cuts metal with very little distortion and easy on the hands. Working upside down with the distance you need to go I think it would be more pleasent than the grinder.

3. 
   sledgehammer | Jan 18, 2007 03:05am | #8

   With a heating bill 12 times what was expected do you really think the problem is the wind? With that sort of wind they should ditch the geothermal and put up a turbine generator and crank the thermostat.

4. 
   oldboot | Jan 20, 2007 07:04pm | #18

   if the house is losing heat through the ceiling and you have no attic ventilation then you will get condensation in whatever insulation is up there.cut a hatch in and find out what's going on.where i live it's a code violation to have a nonaccessable attic space.

5. 
   oldboot | Jan 20, 2007 07:10pm | #19

   my limited understanding of heatpumps is that when it gets cold you get a one to one ratio of energy imput to heat output

1. 
   BillHartmann | Jan 20, 2007 07:33pm | #20

   But this is a geothermal heatpump. So it does not use outside air, but rather ground water/contact which is more or less constant. So it can still put out the same amount of heat.But as it gets cold the house does require more and more heat. So the heat source needs to be so sized.But this is also the cooling system. And AC need to be match much closer to the demand for proper cooling and dehumidification.Now if this is in the far South then the cooling load would be larger than heating and you would not have a problem.But in the north you need more heat than cooling.I don't know how they handle it. Could be using multiple or staging compressors. Or they might have auxilary heating system.Air to Air heatpumps usually have resistive heating elements for auxillary heat or a dual fuel system with a gas furnace that takes over at a certain tempature.But a system like that with electric aux heat and high electric rates can really use the power if the system is not working/setup correctly and aux heat is on when it should not be..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.