I guess it really depends on if air can infiltrate from outside through leaks in the rim joist, get trapped in the fiberglass with moisture. One of the most important parts is sealing out drafts and creating a more tight building envelope. I wish this stuff wasn’t so expensive I would do my whole basement with it. Thank you Todd…I actually wondered about that. Share on Facebook Share on Twitter Share on LinkedIn Share via Email. This problem has been taken care of and the OSB has remained dry. Wood varnish doesn't cover the grain of the wood furniture. Both are about 2 feet out and currently stuffed with fiberglass. In most places it must be protected with some sort of fire barrier, plywood, drywall, etc. are form basement floor to ceiling (subfloor)? Here’s an example, you can see junction boxes in the cavity with wires, etc. Make sense? That sounds fishy to me. We have a large basement that we are working on insulating before the cold winds blow and your site has given us so much great info. Do the floor joists above need to be insulated? Is there any added benefit at all by using a water seal paint on the OSB before insulating with foam board, or is it best to keep it as is? Great web site todd! I have read most your articles and a lot of your FAQs and I found what seems to be two different replies, they were totally different cases so I see why you offered two different solutions but I don’t know which one I should follow. Todd, Having not done my homework, I’ve put fiberglass in all my rimjoists within the past yr. No moisture problem so far. i havent noticed any mold or water/condensation on any surfaces in my basement. I’v heard bits of this before but you put it all together and explain why it works! Thank you! This website uses cookies to improve your experience. Varnish should be applied in temperatures around 70 to 75 degrees Fahrenheit. If I were to decide to run the foam-board the height to the ceiling, should I remove the plastic from the fiberglass batt not to trap it in plastic or is it ok to leave as is…with the foam board on top of it? What I was suggesting the other person do is take advantage of the extra space and use more foam if he could afford it. You don’t need it unless you want the extra R value. Copyright © 2009-2020 Front Steps Media, LLC. Not sure what the “bubble” wrap is that you’re speaking of, why not use a layer of 1″ foam? This will then leave an air pocket behind to the outer house wall, aprox 4-6 inches. Or will proper sealing of the foam board prevent hot air from home reaching the cold rim joist – no condensation issues. Saves time cutting the foam board and increases the load carrying abilities of the I-joist end. I have a couple questions about this topic. 3 bed 2 bath with QUALITY FINISHING throughout. In an ideal world they would be spray foamed. I started by removing the fiberglass and cleaning the areas. I assumed as the roxul in the rim joist was not being covered with drywall, as it will be above the drop ceiling, that it would still need a vapor barrier, so I added the plastic. Spray foam does a great job not only insulating the rim joist but it also seals all the possible air infiltration points. In fact, varnish soaks into the wood finish to enhance the natural wood color in furniture and also protect it from dirt, sunlight, and water. Zero Turn Mower Pros and Cons of Mulching blades. Using varnish offers one of the most natural looks of any product available. I’ve found that joist spacing does vary a bit so trying to cut each one perfectly is nearly impossible. The super tuff-r has the reflective foil on one side, and blue facer on the other, which i believe is still a foil face described as “polymer/foil super Tri-Plex non-reflective facer”. Roxul is a good option in many situations. Let me try and paint a picture for you. He will let us do this if we show him what it looks like after trying a couple joists. Ok thanks Todd. Good luck! I spoke with a local exterminator. Todd, how would you insulate cantilevered joist bays? Awesome… In my basement, they ran the 4″ septic pipes along the foundation walls…literally pinned to the wall. I’d use it on the foundation walls as well but the foil doesn’t do well in contact with concrete. I think leaving the sill plate exposed definitely helps with drying. Honestly, I think it’s drastically different because it’s an area thats typically not sealed well, it’s certainly not an area that’s adjacent to conditioned air like an interior wall is, there are usually lots of penetrations through it, just an all around tough area to deal with. I would like to insulate the rim joists, but we will not be finishing the basement. Elaine – That’s not necessarily the case. Varnishes made from pale gum are generally used on light woods. I realize the XPS needs to be enclosed. Anyway, now I’m thinking of using the Dow crack foam myself and then stuffing the joist area with Roxul after that. This typically consists of a layer of 1/2″ drywall or wood sheathing. By Jenica Lee November 29, 2012. Do you also air seal the space between the where the sill plate meets the foundation? My current plan is to construct the foundation wall, apply a parge coat (probably with Quikrete surface bond cement), coat that with Thoroseal, then secure a SuperSeal dimple mat up to grade, then 3" of foam board or Roxul insulation before backfilling. I just don’t want him telling me it’s fine to spray over it when it isn’t, because he doesn’t want to throw off his schedule. I'm also the Editor-in-Chief and Founder of Tool Box Buzz. Reflectix Insulation has over 20 energy-saving applications for around the home. Correct? Is that necessary? For Example: Foundation Drain, Framing, Cracking, etc. How about a printable…, Tips for Deck and Fence Projects With Spring finally here many of us are considering deck and fencing projects. If this product is OK to use, would I put the blue face against the rim joist, and the foil face sticking out towards the room? Typically we will cut the foam about 1 inch smaller so it can be fit into place easily. Either will work fine. I’d prefer the plastic to be removed if it doesn’t need to be there (because I the spray foam). This application is also very hard to seal up and create vapor barriers. John – Any chance you can take a photo and email it? And I was wondering if the foil faced stuff meets fire code. At low temperatures, it does not cure well. AJ – Renovation work is rough especially with old plumbing and wiring in the way. Bob – That’s a tough situation. When the wind blows, it’s very drafty. Another solution would be installing foam directly over the old siding then installing new siding. Necessary cookies are absolutely essential for the website to function properly. Thanks for all your help, this is a fantastic website. Regarding rim joist rigid foam board insulation – I just read on another site that drywall/sheetrock must be placed right on the rigid foam board (within the rim joist). Jim – Glad to hear things went well. There is no evidence of a capillary break between the footer and first course of block. I’m having a home rebuilt after losing it in a fire. He said a good precaution would be to bait every spring and see if the poison is being taken. So I was going to use foam board where we have drywall on the walls and ceiling and regular fiberglass insulation in the unfinished areas. One other thing I was told is the perpetual monthly return isn’t necessary. For the closed cell spray foam, I am concerned about minute particles that may be emitted into the air over time, that could cause allergies, etc. I read on the manufactures site that roxul is water resistant and is tested for fungal grow and passed with zero growth as it is made of volcanic slag there is no food source for mold growth. I really would like to just do rigid foam but don’t want to have to rip it out in the future. my question is – when installing 1 1/2 inch xps against the block foundation wall. The pipe is about 3-4″ from the rim joist. Trying to answer fire code questions here is certainly not something I can do. I'm back in the same spot as I was in the previous video when we talked about the Roxul mineral wool insulation. before i start replacing everything i did already. Same for non foiled insulation also. Michael – I’m having a hard time understanding your detail. Is that overkill? However, you pretty much destroyed the fire benefit by installing plastic. I was suprised at the air movement coming in from the rim joist area and the dampness behind the fiberglass. The list of uses includes crawl space, radiant floor, attic and walls. Is this OK? Connie – Just go ahead and use 2 layers of 1″. We bought a house with the basement finished except for the large utility/laundry room. Installation of the foil faced polyiso is very easy. Trust me…i’ve seen it done that way and it ends badly! Fortunately, Roxul, made of rock wool, is virtually impervious to moisture, so you're not likely to experience a problem with the insulation. If the rigid 2″ foam board with polyisocyanurate is used, how is it fitted over wires, conduit, pipes, etc.? Then you can install more after. The rim joists are freezing to the touch and air is coming in around the seams. I’ll probably have to add an HRV. Eric – You’ll need to check with your local authority. Frankly either one will work, I just prefer the foil faced in this application to give the most R value possible. Those nails are always very cold and act as moisture condensation magnets! This article will give you information on some of the pros and cons of a varnish finish. The gap isn’t a problem. The code provision does NOT require the fire rated covering to be in direct contact, it just has to keep the area from being exposed. View our Privacy Policy here. MLS® #202027747 R17//Otterburne/*RENT TO OWN OPTION AVAILABLE! Question I have is should I have used Rig board insulation first on the walls the stud it? Most codes deal with rating materials for flame spreadability (sp). He provided us with humidistats for all three floors and told us to monitor to keep humidity in the 35-45 range. ROCKWOOL International was founded in 1909 and today operates worldwide with more than 9,700 employees, with 27 factories across three continents. Honestly I’m not familiar with it’s specifications so I can’t say for sure if it’s going to be ok but I’d guess it will be fine. Maybe take down the duct, insulate, then replace? Looking for solution for the floor. Watch the poison you put out and when it stops being taken you can stop treating until you might see one again. The interpretation varies greatly! Rockwool gives you peace of mind with a fire resistant design that makes safety a high priority in your living space. Any suggestions- and if you would seal the rim joists what product would you use. Se background first: There are a number of cantelevers too, which have just been covered with the sub floor. The trick is getting a vapor barrier on the warm side (floor) or using foam. Thank you for your offering your opinion, and confirming my own thoughts. I think I should be ok – do you agree? Some of the OSB is still damp to the touch. I can not find any stores that carry 2″ foil faced polyisocyanurate, but have found places that carry a product from DOW described on there website as “Super TUFF-R Commercial Insulation features a high-performance polyisocyanurate foam core with three-ply poly/aluminum foil facers laminated to the core, resulting in exceptional durability. The easiest way is to drywall the walls and ceiling sealing off the insulation from a fire hazard. i also noticed a difference with the r-19 in the rim joists. Search for more articles here. Ready to do the electrical My questions are: Is it necessary to install fiberglass insulation between the metal studs /drywall and foam board? Carpenter ants want wood…..the foam happened to be in the way! Thanks for the compliments. Obviously the garage must be sealed from the rest of the house but I have a problem here. However, as you pointed out it can be quite expensive. I have a 20 year old house with open-web floor joists apx 20″ tall. I’m going to use your wall insulation recommendations in my 50 year old basement. Rubbing varnish is often used on wall panels. So for example, a 2′ high wall of foundation, would get handled how? Kim Wisdom says: June 14, 2010 at 11:45 am. Do you apply a waterproof coating and if so, do you apply it to the entire wall or only to the section below grade? I asked about my Dricore system and I will take your advice and try to get foam board behind my walls. It’s really not a wall but simply the vertical portion (or back side)of that space under the bay window. Do you have a reliable code official near you that can check into this for you? I can’t tell you how many rim joist areas I’ve pulled away the fiberglass to find mold, mildew etc. I thought we are trying to keep the wood away from the moisture? This leaves no room for any foam-board, and very minimal space for spray foam…like I said, it’s pinned to the wall. Rim joists are typically riddled with nails from siding, trim, decks and porches. Anytime you can caulk joints in the framing you’ll be doing your home a huge favor when it comes to air infiltration and therefore energy use. Be nice. This is especially true if the furniture is placed beside a window or an area that receives a lot of direct sunlight. None the less the builders put fiberglass batts as insulation over the rim joists, and as I started pulling some of the batts back to see if there was air coming in, to my surprise there were a couple large gaps where cold air was coming in along with some mold starting to show up. What you can’t see is the fact that I’m finishing the ceiling in that area with 1/2″ drywall, which prevents the foam from being exposed. I live in a townhouse where the builder had covered the oriented strand board rim joists with standard fiberglass batts. Gilly – This is also very common. Does the rim joist area need a vapor barrier? Now I’m very concerned about the carpenter ant situation and possibly termites. I’d use a fan….it’s not nearly as bad as spray paint. If I am not putting foam board on the walls … just using fibreglass bats … I was told that I am supposed to leave a gap between the insulation and the concrete wall … is this not necessary? Learn how your comment data is processed. There is kraft faced fiberglass between them now but I would really like to remove it. I hope you’ll consider signing up for my FREE weekly newsletter as well. My township inspector recommend that I fill my entire rim joist area with roxul for the fire code. So if you have the time and patience it certainly will help. If you have a piece of unfinished furniture, you may be considering a varnish finish. I’m totally confused now and don’t know what to do. no? Typically we push it tight to the outside. Oh well. Certainly insulating the rim joist will help keep a house warmer. I wouldn’t be as worried about the moisture (as most wood has a high moisture content in new construction and we spray foam that) as I would be the mold. I also recommend that all bath exhaust fans have a timer on them so you can let them run longer. The cost to replace siding adds $1,000 to $3,000 for removing the old siding. My problem is the wall where the joist beams (engineered) run parallel to the rim board. Here is a link that might be useful: Building Science Corp.: Understanding Vapor Barriers Any thoughts would be greatly appreciated. Second question…there are places where you just do the best you can. Would insulating the rim joists as you suggest help or would it push the cold air into the walls even more? The air space is fine, just be sure the foam board is sealed tightly all around. I can draw this but don’t know how to het it to you. thanks in advance for any help you can provide. Kevin – Thanks for visiting the site. 1. Todd I am installing polyiso on the rim joists as per your articles. In fact, our new home was built this way (this photo comes from my own home) for the simple fact that I had too much going on to focus on this detail. The inspector has signed off the “crawlspace” Thanks Again for your time Bob. There is a vapor barrier under the hardwood floors on the first floor. So this issue is best dealt with depending on the flooring type you use. We are finishing our basement and I think our building code requires foam board be covered with a fire resistant barrier. I recently insulated my rim joists. FYI, I’m in a 1900 farm house, balloon framed, without much insulation. For more information, check out our, Rim Joist Insulation – Insulating Options, Prevent Mold Growth Under Fiberglass Insulation, Installing Cellulose Spray-In-Place Wall Insulation, Insulating Cathedral Ceiling with Foam Board, http://www.homeconstructionimprovement.com/build-attic-stair-cover-big-energy-savings/, http://forums.finehomebuilding.com/breaktime/general-discussion/spray-foam-insulation-and-carpenter-ants, http://www.homeconstructionimprovement.com/how-to-insulate-basement-walls/, http://www.homeconstructionimprovement.com/vapor-barriers-for-basement-insulation/, http://www.demilec.com/Products/Closed-Cell/Heatlok-Soy-200-Plus.aspx, http://www.homeconstructionimprovement.com/bay-window-floor-insulation-detail/, More Home Improvement Cost Savings articles », DEWALT Table Saws DWE7480, DWE7490X, DWE7491RS. A drop ceiling in most cases does NOT count. Also, you talk about problems with exposed nail ends on the inside of the rim joist. I don’t mind leaving it open and above the drop ceiling if no vapor barrier is needed but in my work room (where no ceiling will be installed I would like to have something over it, as roxul dust tend to fall when drafts or vibration disturb it. Steve – Insulating cantilever joists is always a problem. I thought about using foil faced bubble wrap or plain bubble wrap. Both products do have differing off gas issues. The heat won’t bother the polyiso (assuming this is duct work and not a flu pipe). You can always use it up in an attic for an additional layer of insulation. Chris – Fiberglass will work fine in that situation. Your other method is fine as well, just won’t insulate as well :), I have put rigid insulation between the floor joists and on top of my concrete walls … and now I am building 2×4 walls (about 1.5″ away from the concrete walls) and am screwing them to the bottom of the joists. This totals 18″ thick. Thanks so much for all this great info. Can’t be the first time they’ve come across this. Does the insulation sit flush with the sill plate on the inside basement cement wall? Ecohome Aug. 18, 2016, 4:45 p.m. Had to rip out non code wood basement floor and interior walls from previous Owner/Builder. Mainer82 – It sure will! Mike – Bay windows and bumpouts for fireplaces are very difficult areas. From my perspective those joists have a problem regardless of which approach you take, and my bet would be to save on energy and deal with them at some point down the road..which is likely regardless of whether you insulate or not. With the 2″ foil faced polyiso, do i put that right up against the face of the rim joist? I am thinking about buying the Froth-Pak spray foam kit and insulating that way however is it OK to foam over the wires? My question to you is do you think there is benefit to caulking the top and bottom of the rim joist before putting the foam insulation in? I live in upstate NY. My Dad is afraid the cold air will just go to the walls. Would that be ok for thermal protection. How does the fire rating for this compare to the closed cell spray foam? If it were me, I’d use a bleach/water mixture and scrub the area today to kill off the mold. Roxul will work fine for the rest. Either additional layers or fiberglass to supplement. It’s really hard to say if the foam will accelerate any natural tendency to decay. Typically we’ll box around them when it’s a finished space, and install an access door for the clean-out. Or do I box around it with foam board and just mark up where the clean outs are in case I ever need to access them? If we do 2 layers do we foam in each layer as we put them in or just place them in together and foam around the outer edge? and if so would I use foil or craft faced insulation and which way would it face? Please let me know if you find a good solution. I know the junction boxes need to be accessible so how would I problem mask them off when foaming? Thanks. Steve – Great information…thanks for sharing! ;-). So my plan is to use this method when it warms up. Steve – Good luck. However, it appears you are saying foam would insulated and reduce noise. Called the builder just before posting my original message to you and upon receiving my voice mail, sent someone out from their warranty dept. http://www.buildingscience.com/documents/information-sheets/5-thermal-control/crawlspace-insulation/, My question is regarding the preparation of the cement blocks before the installation of the rigid foam. I live in the suburbs just outside Chicago. Just wanted prepped in case SprayFoam installer was gonna try and push us to spray today. Would this be acceptable in your view? Recently some of the foam board manufacturers have been getting testing data to support leaving it uncovered, but it’s important to follow local codes. If they are using closed-cell foam then the plastic is not needed in my opinion. Mold needs oxygen, water, and a food source. Good luck. 2) Will spray foam kill mold that is currently there? I know its cheaper for the builder, but all its going to do is lead to mold, and give the homeowner problems. Currently, there is only fiberglass there (very old and turning black due to wind blowing through). I have a question concering the foam board you used. 300 square feet. Starting with the 6′ height and down, they insulated with fiberglass batt from the rim-joist upward, making the difference to 8′. When insulating rim joists with foil-faced foam board, do you leave the foam board exposed or cover it with sheetrock? Even though most reputable contractors will never install siding over existing siding, there are knuckleheads out there that will say you can do it and it’s not a problem. Hi Todd: I am about to insulate my Rim Joists with 3″ foam with the foil face. Most foam boards actually meet the spec. It’s far more effective than other insulating materials. No question, just wanted to chime in: Thanks to this article I’ve bitten the bullet and begun doing this in my new house, an early 50s Cape Cod. One side of my rim joist isn’t very accesible and is a straight run. Reply. Again, it really depends on your local code. Todd, In follow up to my concern with carpenter ants, etc. Rim joist is 1-1/2″ thick. Due to the offgas issues with spray foam, it’s not an option in my situation. Also, you’d want to get ride of the mold. I need to install rigid foam in my rim joists in the basement. On the inside, then I’d try to seal off that area with more foam as if there were a rim joist above the sill plate. Or do I build the walls right up against the foam board? Steve – My pleasure. Rockwool Comfortboard™ 110 is a rigid, high-density, non-combustible stone wool insulation board designed for use as an exterior continuous insulation in commercial applications. I’ve also seen this application result in mold problems. i get the idea of the foam board against the block foundation however why would the insulation be bad for the rim joists? Varnish may or may not be the best option for your furniture. Not sure I understand the question, is this new construction or retrofit? If you can reach it then I’d install 2″ of foam, seal it in place with can foam. With spray foam you can likely leave them in place. The polystyrene doesn’t quite make it to the bottom of the joists so I have to fill that near 1″ void with something before I install 1″polystyrene to the bottom of the joists to reduce heat sink or thermal bridging. Your picture looks like it’s flush to the inside cement wall. The insulation doesn’t have to be cut perfectly because of the next step. When we do an Energy Star house all the plates get caulked, so between the sill plate and foundation, between the wall plates and sub-floor, etc. This also helps keep it from moving away from the surface. Kieran – I’ve found that using fiberglass is a futile effort. Also, recently, water was being soaked up by the OSB due to the perimeter of the front door needing to be resealed. Mike – This question has come up so much that I just wrote about it here: http://www.homeconstructionimprovement.com/bay-window-floor-insulation-detail/, I recently did some of my header spaces with foamboard and sprayfoam, the sprayfoam pushed some of the boards out a bit so there is most likely a 1/4 inch gap btwn board and rim joist in some areas. Fiberglass insulation doesn’t work very well in this application. 2x4 furring, not 3/4". Disaster team cleaning up the mold tomorrow. What do u think? I caulked the top and bottom with silicone, cut the foil faced with a circular saw and miter saw. John – We have several articles on the site that show you different ways of using foam board. This creates great insulation value but it does require some special details at doors and windows to address the added thickness. My sill plate is anywhere from 0 inches to 1 1/2 inches from the inside face of my foundation wall, bad construction job there. I bought (had to special order) 2″ foil-faced and use Loctite foam to seal around. It might be the best option due to the tight area. I think you’ll find that insulated the rim only will help on the main floors more than the basement, but it certainly will make a difference. It’s the only way our little site will rise to the top above all the corporate junk that floats around the Internet. The basement gets humid in the summer, even with a dehumidifier. Having said that, if you cut the foam just a bit smaller and then seal around the perimeter with spray foam from a can you’ll probably end up doing the same exact thing.
Interesting Facts About Stilt Houses, Dovii Cichlid Size, Jl Audio 12w3v3-4 Wiring, How Much Is A Zoeller Sump Pump, Beth Ehlers The Hunger, Neal Schon Songs, Lancer Evo 9, Dip Mix Packets, Little White Bugs In Crested Gecko Tank, Japanese Savoury Snacks Uk,