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Attic Moisture: Mold in Attic

I have moisture in my attic. I have rusted nails through my sheathing and it looks like mold is starting to form.

I have soffit and continuous ridge ventilation, and the bathroom and kitchen vents are vented to the outside. What can I do?

Our Answer

Moisture in the attic oftentimes can be frustrating.  More so when you have provided what is considered all the right things in ventilation and exhaust installs.

To understand why this is happening you must figure out what the moisture source is.  It has been my experience when issues such as yours has come up that the moisture source is coming from the inside living area of the home and is being drawn into the attic through was is called Stack Effect.

Stack Effect is the result of poor air sealing both in the basement and in the attic combined. Believe it or not, the basement has a lot to do with the performance of the attic vent system.   What happens is as the air in the house is warmed up it rises. Much like a chimney.  When this happens it moves up taking indoor moisture with it.  I am sure you or someone you know has a home that suffers from dry air in winter months?  This is all caused by air moving out of the home. When we think this air is moving out of the walls, and it is, most is going up and out through the roof.  The result is the moisture condenses on the colder areas of the attic. The nails and the area closest to the ceiling which is around the soffit locations.  As the air move up in the middle of the attic it tends to cool down and mix with the air in the attic and is drawn out through the vents.  But when it enters near the soffit it hits the cold roof before it mixes with the air in the attic and condenses.  This is why in most cases we find the attic stained near the soffit areas. But quite often then not we blame the soffit area for pulling in the damp air in that location.

In any case we need to stop the air flow entering into the attic. This will stop the moisture flow and the result will be no moisture, no mold, and no rusted black stains where the nails enter into the attic.

To do this we must first find were the air is entering. This is easy.  If the attic has insulation, pull it up wherever there is a wall below. This can be the outside wall area or where any wall that makes up a room below is located.  Look at the insulation. If its fiberglass you will see black stains in the fibers.  This is dust.  This dust is the result of air movement with the fiberglass acting like a filter. This is a sure fire method of finding exactly were the air is entering.  You will find it wherever wires enter into the attic, plumbing pipes, chimney come up and out. And even around the access hatch or staircase is placed. 

To fix this you need to purchase spray foam insulation.  I use the window and door type as it is a little less foamy then the regular stuff.  The standard foam in can expands way to much and can get a bit messy wen working with it.  In anycase, regardless of what foam you purchase, you need to pull up insulation and foam both sides of the exposed board that is the top plate of the wall below. Any wire openings you need to do the same thing. Plumbing as well.  When you get to the chimney you need to baffle this. Normally there is a fairly large space between the brick and the framing of the ceiling. This is done for fire protection. Purchase thin metal sheets and form and cut them to fit around the opening blocking off as much of the hole as you can.  Then using fire blocking foam.  Seal off the metal to the chimney and framing area.  Once done this would be a great time to add insulation while your up there.  But your not done yet.

Go to the basement and do the same thing. Purchase foam 2" boards and fit them into the mud sill area over the block foundation wall.  Using the high expansion foam (the messy kind) spray around the edges of the framing, place the precut foam boards into this space and foam them tight to the wood.  This will air seal the wall so no air moves up it towards the attic.  Foam all the pipe openings, wire openings and around the chimney in the same manner as you did in the attic.

Once done you not only will prevent this moisture from collecting in the attic on the underside of the roof, you will save a lot of heat and increase your comfort level by stopping drafts that pull the moisture out of the house.

In effect this is the same thing we do as Building Performance contractors  only using large foam machines instead of the little cans.

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Attic Ventilation on Concrete Clay Barrel Style Roof in South Florida

I live in South Florida between Fort Lauderdale and Miami. My house was built in 1998. When I bought the house in 2010, I noted that none of the houses in my planned neighborhood, all built by the same builder, have attic vents near the ridge of the roof or anywhere else on the roof.  The house is on one floor and 3100 sg ft.

We all have numerous soffit vents, but no vents for heat to escape near the peak or ridge of the roof. I'm very well versed in home construction and am aware that some clay barrel style vents are difficult to spot. This is not the case here. We only have soffit vents.

That leads me to several questions. Was this designed like this  on purpose? If yes, why? Perhaps there is a reason for this in a high humidity climate that I'm unaware of. Was the builder just cutting corners? Where I moved from in Virginiia, all houses had soffit vents and ridge or vents near the peake to allow for airflow.

I am also planning to upgrade my 4-5" of current batt insulation in the attic with blown in cellulose to bring it up to an R49. Our AC units, both fairly new, corrrecltly sized and operating as desinged, can't get the tempeature in the house to below 75.

So, what are your thoughts on? 1. Do I need to add attic vents? If yes, what type and how many for my size house?

Thanks in advance for any advice you can share.

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Roof Insulation

My girlfriend has a large 3 story log cabin here in Alaska. The entire roof from the top plate of the walls was removed then 24" BCIs were used to create a 'cold' roof and a 'vaulted' ceiling inside. We are going to screw 2x2s horizontal, (paralell),  between the BCIs as a back stop for the 2" blue board that we will install between the BCIs. Then our intension is to, (from the bottom side), spray urethane until it is flush with the bottom of the BCIs.                                                                                                                                                     What is the appropriate thickness that the urethane should be? There will be plenty of air space between the roof sheathing and the top side of the blue board for air flow and we have open soffets at the ends as well as a ridge vent.                                                           We now know we went overboard on BCI height, but I guess on the bright side air flow won't be an issue.                                               In regards to insulation thickness, we don't know at what point we no longer gain anything and are wasting money.                                                                                                                                                                                                                                                          Thanks, Tom

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Can I Insulate My Roof Without Removing It?

What is the best way to insulate a one-and-a-half story home? Our house was built in 1952 and has no soffit vents but does have attic vents. I did some research and am leaning toward using Icynene closed-cell foam to create a "hot roof" - but what I've read is to do it right we'll need to either remove the sloped ceilings or remove the roof.  Is there a way to insulate our home properly without removing either the roof or ceiling?

Our Answer

I'm guessing you have what's called a cathedral ceiling - that is, roof rafters, insulation in those rafters, drywall under it and plywood above it.  Like a rafter sandwich. 
For starters, Icynene is an excellent choice.  I've used it myself, with fantastic, money-saving results. In terms of installation, if this is indeed a cathedral ceiling, then yes - the roof or drywall have to be removed so you can pull out the old insulation, apply the Icynene, and close it back up.  I essentially did both in my upper attic roof, in places where I could get under it.  In the attic overtop my home's addition, I had little clearance, so I had to take the roof off and spray the Icynene across the ceiling.  Even though it was a lot of work, it was worth it.  Icynene seals and insulates, and is a very cost-effective way to keep your home heated. 

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How to Insulate an Attic That Has No Soffit?

What is the best way to insulate the floor of an attic if the house does not have soffit vents - or any soffits at all?  There is a ridge vent and two gable vents for ventilation.  Do I need to install special soffit-less vents, or can I insulate right into the corners of the attic, right up to the roofing boards?    I live in New England and am concerned with ice dams.

Our Answer

There's a type of vent called an edge vent, specifically designed for this purpose.  Edge vents basically extend the roof edge by a few inches so you can pick up space for soffit insulation.  A ridge vent is good, but is only half the equation. 
Unfortunately for your situation, edge vents are best installed as part of a larger roofing project.  The roof basically starts at the edge of an edge vent, so it's difficult to add them after the fact. 

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Do I Need to Pull Up My Attic Floor to Insulate?

I want to add insulation beneath my attic floor, but I'd have to pull the attic floor up to do it.  How will this effect my second floor ceiling? I am worried that the ceiling beneath it is protected by the attic floor.

Our Answer

Certainly your attic floor protects people from stepping through the ceiling beneath it, since that ceiling is not designed to hold weight much heavier than the weight of insulation.  But you probably don't need to remove your attic floor to insulate the space.  You could simply lay insulation above the attic floor - unfaced fiberglass batts, specifically, laid over the floor in the areas you wish to insulate.  If you use your attic for storage, consider consolidating those stored items and keeping them in one area of the floor that you leave exposed.  

Now, if you presently have no insulation whatsoever between the attic floor and the second floor ceiling, take that floor up and insulate it - and restrict the workzone to responsible adults who know where they can and can't place weight.  But if you simply need more insulation in your attic, the easiest bet is to put it over the attic floor.

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Easy Repair For Loose Drywall Tape?

There is a seam in our upstairs ceiling where the drywall tape is peeling up.  I know I can repair this, but I am worried about the cause.  It's just in one little section, maybe two feet long, right above this ceiling is the attic.  Should I be looking into attic humidity levels?  Is there a way to test that?  Our attic has a vent on the side but no roof mounted vent.  I just want to make sure I'm not covering up a potential problem by repairing the dry wall tape.

Our Answer

No need to read so much into a loose tape seam.  It rarely indicates a serious problem. Ceilings in particular expand and contract along seams as well as intersections with walls, causing tape to loosen.  
To fix this, you need to cut out the old tape with a utility knife, because this loose tape will never reseal.  Next, apply fiberglass drywall tape, which is mesh and perforated.  You can trowel and spackel across and through that.  Finally, apply a drywall compound on top of the fiberglass tape to restore the seam.  Once that's complete, you can prime and repaint.  

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Insulating a Cathedral Ceiling

We bought a house made in 1960 in southern California. It has vaulted ceilings and no attic. There was never any insulation put in the walls of the house or above the ceilings. During the summer it gets really hot upstairs. We have installed ceiling fans. There is no air conditioning. We have not experience a winter yet. Can we install/blow installation into the walls/ceilings? Would it be worth it?

Our Answer

This is an unusual situation and, unfortunately, quite the undertaking no matter which route you take:
There are two ways to insulate a cathedral ceiling: 1) Insulate the rafters themselves, which requires leaving an inch and a half between the top of the insulation and the underside of the roof sheathing to allow for ventilation.  Air needs to move to take out heat in summer and moist in winter.  2) Add insulation on top of your roof.  This would be done the next time you replace your roof shingles.  You'd add 2-3 inches of foam board insulation on top of the roof, and then more plywood, and then the new roof. 
Both of these are major projects in your scenario because your ceiling is already constructed.  If you opt to insulate the rafters, consider removing drywall for this project, and then deepen the rafter by adding additional material so it can hold more insulation.  Or better yet, use spray foam insulation to fill entire rafter bay, because it doesn't need to be ventilated.
Good luck!  If you tackle this project, post pics to Money Pit's Facebook page letting us know how it goes. 

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Energy-Efficient Insulation

We are planning a complete renovation of a caboose into a guest home/office in New Jersey.  We plan to install electric heat, possibly with some in the floor.  Since the shell is metal and lined with wood, what would you suggest as the most energy-efficient insulation?  We expect to be removing the interior and replacing it with wood. It does not appear that there is enough air space to use blown insulation without removing the wood. We would appreciate any suggestions to take on this project.   Thank you, Eloise Hagaman

Our Answer

First, congratulations!  This sounds like a really fun project.  That said, keep this in mind: Electric heat is no doubt the most expensive way to heat any building.  If you're planning to use this caboose year-round, you might want to rethink whether or not you should use electric radiant heat. 
Another option that comes to mind is a ductless heat pump.  This is also electric, but it costs only half as much to operate as radiant heat.  Since your caboose is presumably a relatively small area, this might be the most efficient way to accomplish the talk.  In terms of insulation, that spray foam insulation might be more feasible than you think.  When those walls are stripped, you should be able to easily apply spray insulation to the interior.  It comes with the added benefit of soundproofing, and is a very energy efficient insulation.  I recently had Icynene spray insulation installed at my house, and the resulting impact on energy bills has been nothing short of dramatic. Good luck - and please pass along pictures when the project is complete!

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Uneven Heating and Cooling Throughout House – What’s the Cause?

I have a brick three-bedroom rancher built in 1974. We blew insulation into the attic when we moved in, and last year installed brand new windows throughout the entire house. Yet when I close the doors to two bedrooms they get warmer in the summer and cooler in the winter. A lot of air that comes from the registers. There are also 31-inch air returns on the walls in both rooms. Is it possible that these are too big for the rooms and causing this problem?  Or could it be something else?

Our Answer

If registers are letting air into rooms from unconditioned spaces, like an unfinished basement or crawlspace, it could be the cause - or at least a contributing factor.  Hire a HVAC contractor who can measure airflow through those registers.  If the registers are damanged or perhaps not even fully open, it could account for differences.

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Sunroom Addition and Insulation

I'm having my covered patio converted into a sunroom, and was advised to have this area insulated.  I contacted an insulation company who told me they wouldn't want to bother just insulating that small space, but would be happy to insulate the entire attic, which is already insulated...for 600 bucks.  So I'm thinking of doing the insulation myself.  The problem is the area in question is hard to access.  I would have to crawl back there, and of course run the risk of stepping through the ceiling, etc.  Any advice on how I can accomplish this without putting a hole in my ceiling?  Also I have fiberglass insulation, but obviously blowing in insulation is not an option for me, so what kind of insulation should I buy?

Our Answer

I'm seeing two questions here, so let's address both:

First, I often encounteer sunrooms that are poorly insulated.  Typically sunrooms overheat in the summer and are miserably cold during winter. so yes, it's wise to insulate a sunroom properly. 
But a more pressing concern: A sunroom on top of a patio is a potential violation of building codes.  Patio construction is not the same as home construction.  Typically, patios are poured on top of dirt, with no foundation.  Converting this into "living space," then, will most likely violate building code and could potentially reduce the value of your home.  I strongly advise looking into this before proceeding, for both safety and resale reasons.  

You ask about attic insulation.  More insulation is always good, but if the attic is terribly difficult to access, you should consider having this done professionally.  Make sure that if fiberglass insulation IS used, you allow for proper attic ventilation.  Ridge and soffit is the most popular ventilation for these scenarios, but no matter how you do it, it's crucial that you have free-flowing ventilation throughout the attic; otherwise, the attic will overheat in the summer, getting the fiberglass insulation damp and making it ineffective in winter.  

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Attic Insulation in Old House

I have an old farmhouse, vinyl sided, with no attic insulation. There is no ridge cap, soffit or side vents. Can I lay down fiberglass insulation on the floor of attic and/or between rafters? What are my options?

Thanks Harley in Swansea

Our Answer

Good or bad an old farmhouse is drafty as I'm sure you know.  The best thing is to combine the proper amount of attic ventilation with insulation, so the insulation stays dry.  The first step is to add 15-20 inches of insulation in the attic.  Lay it across the floor joists.  This will make a huge difference in your comfort.
To add some additional ventilation, add gable vents if they don't exist.  Gable vents are not as efficient as ridge and soffit, but gable vents plus the drafty house should provide enough ventilation for the insulation to work properly.

When you need to reroof, be sure to add a ridge and soffit vent system for ulimiate vent efficiency.

Another insulation option is to consider spray foam - products like Icycne are perfect for old farm houses.  It can be directly applied to the underside of roof sheathing.  In this case the attic is not required to be vented and the spray foam insulation will insulate and seal drafts at same time.

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Insulating Walls Without Removing Drywall?

We recently remodeled the kitchen in our 1954 brick ranch and discovered only "Insulite" fiberboard insuation was used.  My understanding is that is only an R-1 rated insulation, so when we replaced the drywall, we added R-15 batt insulation.  My question is, how do we insulate the remaining walls of the house without replacing all the drywall?  Is this possible?  What's the best way?

THANKS!

Mary

Our Answer

Mary, your home is a good candidate for blown in insulation.  It can be blown in from interiror or exterior walls.  A small hole is drilled in the wall, through which insulation is blown.  It expands to fill wall cavity, the hole is plugged, patched and refinished.  Holes ared drilled into each and every wall cavity.  Sometimes two holes are needed, one higher up and one low to the ground, to make sure the entire cavity is filled.  Professional insulation companies have the proper tools and techniques for this.  They can even scan the home with infrared equipment to determine exactly where insulation is missing.

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Frost on Interior Walls

We built a ranch style home in 2012.  When it is extremely cold (below zero) and the wind blows we find areas of frost on the the interior walls @ ceiling level.  The exterior walls are 2x6, with blown in fiberglass insulation.  The attic is insulated to 48 R with blown in fiberglass.  The attic is ventilated with soffit vents and ridge cap venting.  Interior humidity runs 34-38%. We have Anderson 100 windows and do get moisture and ice built up on them as well, I get the ice on the windows but struggle with frost on the interior walls.  The general contractor and insulating contractor are puzzeled as well, but are still working with us.   Looking for ideas on identifying and correcting the problem.  We have lived in SD all our lives(55 years) in numerous houses both new and older and have never seen any frost on interior walls. Thanks for your help

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How Much Insulation?

We live in an older 1949 home. There is no insulation under the floors, limited original insulation in the attic. My "crawl space" is bigger/taller than most and often feels relatively warm. I'm wondering if I wanted to start adding insulation (we are on a very limited budget) would it be better to add insulation in the attic, or to start putting insulation under the house?