I tried this last week and got nothing back but perhaps I didn’t enter it correctly so I am trying it again. I am not in the building trades so I am seeking some help and advice from the pros.
I contracted to have new vinyl siding applied to my existing home in the Detroit area which included foam board insulation underneath. The crew removed the old aluminum siding and the trim caps around the existing vinyl windows. They applied 3/4″ foam board to the work area and siding channels around the effected windows and corners. This was followed by the new vinyl siding and aluminum trim and gutters.
The house looks very nice but the interior has very cold zones which have become a big problem. I checked the windows to be sure they are closed and all seems good there. I called the contarctor out about this condition and he had the installer caulk around the trim where it meets the brickwork but it didn’t cure the condition. I might even be concerned about water drainage now that the excape route is blocked.?
I called the contractor again and he claims the project was done correctly and we must have another issue that is creating the problem. I questioned him about taping the seams and edges of the foam board insulation and he said it was not necessary and would trap moisture against the home. The problem with that explaination is that all of my follow-up to this on the internet DIY videos all show the steps to properly tape the seams, joints, including windows to prevent air leaks. I should also mention that I don’t have this problem at windows that weren’t touched by this project.
Should I expect to have all of the insulation joints/seams sealed?
What is the accepted industry standard for this type of application of foam board?
Did I get a contractor who has (hopefully) the correct materials but is lazy in applying them to ensure they are effective?
I thank you in advance for any advice/info you can provide.
Zeno Potas
Replies
Cold spots
You are saying the rooms with new insulated vinyl siding are colder than they were with ould alum. siding and no insulation?
What kind of supply heat and returns are in those rooms? Sometimes tighting up the building envelope and adding insulation can excaberate a poorly designed or installed heating/cooling system. Poor supply or not enough return air in those araes can cause an imbalance that manifest itself as a hot or cold spot.
Before you blame a siding contractor for this, I would have good HVAC contractor look over your system design and maybe run some load calculations. You may just need a system air balance or any number of small tweaks to get you comfortable again.
Thanks for your input. Our home is heated with forced air gas system that was replaced 6 years ago. There were some duct flow adjustments made shortly afterwards but can't say we were unhappy with the furnace performance. Our cold zone problem extends across several rooms, all facing the front of the home.
Z. Potas
Balance
Still sounds like a air balancing problem to me. Even poorly installed insulation on the outside of the home would not cause you to develope cold spots. By insulating the outside you have likely sealed some air leaks and as a results changed the dynamics of the interior air flow (balance).
Having a new forced air furnace doesn't always mean you are getting better performance. A good HVAC contractor would have measure every room of your house, looked at window performance and the building envelope integrity along with what ever insulation existed. He would have modeled all of that information into his load calculations to size the new unit for the home. Within those calculations would have been individual room loads and the number of btu needed to meet each of those loads. Supply and return duct runs are then sized off of those same load figures. He would then have given you recommendations for both equipment and a distribution system, along with the same for sealing and upgrading the building insulation/envelope.
If you had a contractor that did all of that for you, he was likely the highest bid you recieved, and his competition beat his quote by 25 to 40%.
The last guy that made an improvement may not be the guy that caused your current problem. You may need thermal scan, blower door test, and air balance test to figure out what is really happening.
Good Info
Dave,
You are offering some interesting things to look at to fix my problem but I see it a little differently. The siding/insulation guys where the last ones on site and might be easy to pick on. I would like to exclude them before moving forward (or backward as it may be) to other possible causes.
The questions that haven't been answered up to this point; was the insulation applied correctly, taped at all seams and joints to the accepted industry standards? I didn't see any and the contractor claims it wasn't necessary.???
I wasn't planning on going all the way back to the original builder first and work towards the siding/insulation contarctor. That doesn't seem to be the right direction to take even if I am not in the trades.
I still appreciate your effort to help.
Z Potas
Is not taping the foam a best practice? No. Is it a bad practice? No. You would never be able to tell the difference if it was taped or not.
Has anyone even looked at the ductwork? How do we know that something hasn't come undone? I don't understand why pinning this on the siding guy makes sense if he ADDED insulation to the entire exterior of your house - your house is better insulated by a long shot from no insulation and aluminum siding!
Insulation tape issue?
Don,
Once again, I am not in the building trades so I am relying on the info from those who are and it seems like the conflict is in the trades. All of the "how to install" info I got online says taping is required to air seal the foam boards as well as prevent water from getting behind the foam. You are telling me that the tape is not the way to go?
Allow me to add addtional thought to this problem. The vinyl windows are about 5 years old and were capped with an aluminum material and sealed (calked) on all edges to the window and the existing aluminum siding. This seemed to work well to prevent drafts/air leakage. The vinyl siding/insulation guys stripped all of this away to install their system and it appears they failed to seal the areas they just removed. If I needed to seal the window areas myself now, I would need to remove their work.
Getting back to the ductwork, I have a full basement which has the ducts exposed for the most part. I checked the entire system and see no loose joints and I am in the process of sealing all of those joints for leaks.
Does the building trades have a consensus on the use of tape/calking/sealing the joints on exterior foam board insulation. When should it be used and when is it best not to seal and why? I still look forward to excluding the siding/insulation first.
I still appreciate all of your input but could use some with better direction.
Z Potas
Some Questions:
There are conflicting objectives that need to be balanced in regard to the issue of sealing the exterior surface. Too much sealing can cause the wall to not be able to “breathe,” which means to dissipate any water vapor migrating outward from the heated interior. Too little sealing can cause too much outside air infiltration, degrading the insulation performance and possibly entering the living space.
I have a couple questions:
Do you have an airtight vapor barrier under the finish on the warm side of the wall?
When they installed the foam board, I assume they laid it over the exterior sheathing. What type of sheathing is it? Was there asphalt felt covering the sheathing? If so, did they remove it before putting on the foam?
What I am wondering about is whether it can be any less airtight on the outside now than it was before they did the work.
Regarding the breathing issue, if you do not have an interior vapor barrier, a well-ventilated exterior is the best way of dealing with any condensation in the walls. That way the outward migrating vapor can escape as quickly as possible and be expedited in that escape by the some limited infiltration and drying action of the outside air. So, if this is your setup, then the foam joints should have been left unsealed.
There are four basic arrangements that are possible:
1) An airtight interior vapor barrier with a backup vapor barrier of exterior foam sealed with its inward surface above the dewpoint.
2) An airtight interior vapor barrier with an exterior foam layer unsealed to promote ventilation of any vapor breaching the interior vapor barrier.
3) No airtight interior vapor barrier with exterior foam unsealed to promote ventilation.
4) No airtight interior vapor barrier with exterior foam sealed.
Any of those first three arrangements would be okay. What you don’t want is arrangement #4; that is, no airtight interior vapor barrier with exterior foam sealed. That may have been their rationale in leaving the joints un-taped.
I am guessing that you have arrangement #3.
However, aside from these issues with vapor, I do not see how the house ended up colder unless the materials they removed were providing more air sealing than the amount of air sealing in the materials they added. They removed your siding and added new siding. They also added foam board, but with open joints. Did they remove anything else?
Windows will be sealed to the house and not to the siding - I'd bet the windows were sealed to the aluminum on the surface, but that's mostly cosmetic, and to prevent air infiltration they have actually been sealed to the sheathing - if they are replacement windows they may be sealed to old window frames and those frames are sealed to the sheathing. The siding doesn't usually block air movement into a house - it wouldn't even be possible for aluminum or vinyl siding to do that because of the many small gaps at every joint.
Tape/no tape?
Don and Kdesign pretty much covered that isssue.
Air infiltration or exfiltration is hard to trace without a blower door test. If it is extreme you can sometimes find gross leaks by using canned smoke or an incense stick, but they can be hard to interpret. Weather conditions and wind directions can greatly influence interior drafts, as well as if the furnase is on or off.
The window sealing scenerio you have described is a little vague. Was the window replacement job a full replacement type or just the sash type? As Don pointed out the exteior sealing of window units is done with flashing tape at the sheathing to window boundry. Caulking at those areas is only effective for a short time. It will eventually fail, no matter what the manufacturer claims or someone tells you. Better caulks fail much later, but my experience is that they too eventually fail. I look at all caulking as a maintenance item and if it is buried behind something like siding the first signs of failure can be water damage seen inside the home or mold blooms. Air infiltration/exfiltrations are also a symptons but is so hard to find that other damage occurs before the search even begins.
That brings us back to a blower door test as the means of locating you possible leak points.
If I'm understanding this correctly the entire exterior of the house now has 3/4" of rigid foam where it had none in the past - that's a big improvement. Changing an entire house's insulation will change the heating and cooling needs of each room - some will be warmer, while others will be cooler because the duration of the furnace cycling on has changed.
You say the front of the house is where the colder spots are - I'm with the others in suggesting that a good hvac guy is the best person to contact to get your problem resolved.
Many Thanks for the Info
Members,
You have provided me with a lot of useful info I can use even if it may be conflicting between those who answered. I believe I will look to a whole house door fan leak test to find the problem(s). I had this done several months prior to the siding work and thought I made most of the corrections they pointed out. I hope this will provide the direction I need to take with this problem. Thanks again for your help.
Z Potas