© 2021 The Taunton Press, Inc. All rights reserved. Member. No, there is no venting. You can furr the rafters down to get more space for insulation. Polyumac supports its GatorBoard line with a cost-effective kitting service that includes the capability to work directly from customers' CAD files. Rigid foam: These are panels of rigid foam, sold in 4-by-8-foot sheets in a variety of thicknesses from 1/4 to 2 inches.It is also sold in large bundled panels, joined at the ends accordion-style for use as an exterior sheathing material. The only problem is any substantial amount of fiberglass, like R21, is 5.5″ thick. Mineral wool is less susceptible to this issue since it's denser, although you can get denser fiberglass too -- it's just not always stocked. Become a GBA Prime member and get full access to GBA articles, enyclopedia, videos, CAD library, and more. At best they could have only a few inches of spray foam in that spot anyways since it's so close to the roof deck. I already have 2″ of spray foam in there, and the bays are only 5.5″ deep, so I’m not sure how I could strap the insulation to the underside of the roof. Poor Mans Fiberglass, Permanent Exterior Paint, Never Paint Again (almost), Waterproofing With Out Epoxy, Fiberglass Epoxy Allergy Relief: Back in 2011 I built a teardrop camper, at the time I needed … You can use epoxy resin over polystyrene foams, but not the polyester resins. So at least in my mind, the "flash-and-batt" approach seems likes the easiest, cheapest, and best method? Finally, many resin materials are formulated to be used inside a mold and do not work properly when exposed to air. It sounds like at least part of the roof is unvented dense packed at R19. Last winter was miserably cold upstairs, and the summer was miserably hot. Higher end memory foam mattresses that are made in America – like Amerisleep – don’t use fiberglass in their beds. A blower door test would be valuable if it has not been done. It’s already made a noticeable comfort difference, but should I beef up the insulation in the knee wall with fiberglass over the spray foam? Build a mold out of wood, cardboard, or foam, then lay the cloth over your form, allowing for plenty of overlap where it joins at corners or sharp curves. Can you put blown insulation over rolls? It’s important to air seal the area before you add new blown-in insulation so it … The fiberglass that was against the drywall was removed and not replaced. GatorBoard is ideal for a very wide range of marine, road/rail transportation, aerospace and industrial applications. There is no reason you can't install some extra fiberglass over the spray foam though, it's done all the time. GatorBoard is a closed-cell, high performance foam core that is reinforced with fiberglass cloth and continuous strand mat. The attic flat has a power fan in it but there's barely any room up there. Similarly, it is asked, can you put fiberglass batts over spray foam? Then the slope and the attic flat were stuffed with R13. Usually, this means starting with a female mold. Styro-Shield is a Polyester-based product that uses MEK-P and will provide a protective coating once hard. The fiberglass skins used in foam sandwich are much thicker than in plywood sandwich. This feature has been temporarily disabled during the beta site preview. This step can be adequately done in an hour or half.Step 2: Once you’re satisfied with the shaping and final outline, you can wrap up the plug with a layer of packing tape to stop the epoxy from seeping into the foam. Expand Collapse. Allow the fiberglass to harden fully -- … For the slopes they dense-packed cellulose to R19, and for the attic flat they did cellulose to R52. FAQ: Why Do Some Builders Avoid Foam Insulation. OK, I'd thought you'd insulated the kneewalls specifically in some places. Or get the spray foam company back to apply another inch, and add up to R-40 at the interior. I will put down a vapor barrier paint when repaint the drywall. Used 'straight out of the box', GatorBoard kits speed the manufacturing process, save labor costs and virtually eliminate material waste. After an exhaustive search and brief "horrible" experience as a panel sales rep, I decided to build my own panels from scratch. Also, non-artistic builders find it intimidating to sculpt the shapes freehand. Spray foam insulation for both types starts at about $1.50 per square foot and can cost more than $5.00 per square foot when a thick application is applied. I then came across FRP manufactured composite panels. Ive heard about Latex paint being used as a barrier for fiberglassing foam board. In short, you carve the shape you want in foam, cover the foam shape with layers of fiberglass and epoxy, and then get rid of the foam. https://www.buildingscience.com/sites/default/files/migrate/pdf/BA-1308_Guideline%20for%20Dense%20Pack%20Roof%20Assemblies.pdf. Modern variations sometimes use an epoxy resin or vinyl-ester resin and carbon-fiber-cloth over urethane foam, like the composite used to … Hopefully someone can give me some insight on a couple of problems I have: I have a two story home in Texas. You must be a magazine subscriber to access this feature. Re: Will fiberglass resin eat through foam? Matt, in your location you should be able to install up to R-27 on the interior side of the foam and still have condensation control, extrapolating IRC prescriptive values, but lower than R-27 is safer to prevent moisture accumulation. The sloped roof was dense packed as is; it would have been a huge mess and cost to remove the drywall. There is 2 dormers on the front and a big shed dormer/extension across the entire back. In the Lost Foam technique, the foam is the mold and you dissolve the foam (or just part of the foam to keep more rigidity) when the piece is done to leave you with the resulting part. It is commonly fabricated in foam core sheets, or it can be blown or poured in place for insulation and buoyancy applications. GatorBoard will never rot and will maintain its strength regardless of the length of time that it is exposed to water. Some brands like Purple do, but they infuse the fiberglass into the material rather than layering it so it won’t spread all over your room if you remove the cover. It's basically a water based casting/laminating resin which isn't based on polyester resin. Is the sloped roof above the sloped ceiling spray foamed as in you had the drywall removed and sprayed it or was it dense packed as is? So the areas with spray foam can definitely be flash and batt as Michael said. This idea came to me from another build involving carbon fiber laminated over foam board. It's water based and water soluble, so you'll probably find it won't eat into the foam. The original setup was faced R19 on the drywall, and that was it. Much of the problem was due to the rough and wavy surface that usually resulted when these materials were not used inside a mold. - 1060 E. 30 St. Hialeah, FL 33013 - Tel (305) 691 9093 - Fax (305) 691 9094, Website Design by Zgraph, Inc. Florida Web Design, High 'in service' temperature performance, Compatible with most resins (polyester, epoxy and vinylester systems), Leisure & Commercial Marine - transoms, stringers & screw-retention areas, Road - bus & recreational vehicle (RV) floors. We used polyester resin and glass cloth laminations over a core of rigid urethane foam boardstock (fiberglass over foam). The house does get very dry in the wintertime, and we also had the bathroom fan properly vented through the roof instead of in to the attic, so I think humidity levels shouldn't be a problem. If you wrap the top plates with the rigid foam that helps with thermal bridging too. Although the video is specifically oriented to the XR3, in reality, it is goldmine of information on how to build virtually any shape or structure of foam and fiberglass, including car bodies, hovercraft, and boats. Another post with details on your assembly might yield some useful feedback from others. Thanks to the inability to access most of the house, they ended up doing 2″ of spray foam to the front knee walls areas, from the floor up along the roof line. If this is the case, you should understand that there are some moisture risks to the unvented assembly and how to mitigate them. Michael covered the fiberglass questions well. 2″ of spray foam is only R12. No Air Seal Is Created. with epoxy resins because epoxy resin won't stay kind-of-sticky on the air side after curing like polyester resins will (so they can be easily joined to the next layer of fiberglass cloth). Either curved laminated beams with a 1/4 inch plywood top skin or structural foam with fiberglass skins will do the trick. Use a razor knife to cut the mat. Rigid foam over fiberglass wall batts in attic. Fiberglass, cellulose, and foam dominate the conversation, but the breadth of insulation products is wide, including cotton, straw, hemp, and sheep’s wool, just to name a few. Rigid foam insulation uses one of three materials: high-quality, green-friendly polyisocyanurate; extruded polystyrene; or expanded polystyrene. GatorBoard Fiberglass Reinforced Foam Core GatorBoard is a closed-cell, high performance foam core that is reinforced with fiberglass cloth and continuous strand mat. Take your time, and cut very slowly and acurately. Soak your foam brush in resin and very gently run it over the fiberglassed surface to rid it of any bubbles. https://www.youtube.com/playlist?list=PLuMPs5qUmnoTlBkwedPTYQXe98uv4rsCT If you enjoy … There is no reason you can't install some extra fiberglass over the spray foam though, it's done all the time. Cut the layers of fiberglass mat to the specific size that is needed. Page 1 of 2 1 2 Next > twannabe. Should work well and perfectly safe for those areas. Follow my journey as I build my first foamie camper. Thankfully, the parts that are dense-packed have no penetrations at all. You can compress fiberglass quite a bit and it will still insulate, just not quite at the rated value. Which side of the knee walls was the spray foam applied to? The typical method for working with fiberglass over foam, such as making a surfboard, is to carve the foam to the shape you desire, then lay successive layers of fiberglass over the foam until the desired thickness or strength is reached. If it was just dense packed as is, you want to take steps to mitigate potential for moisture issues. Over the weekend I ripped a sheet of plywood into 2" strips to use in my core build, cut the bulk floor foam pieces and started putting them together. As a result it is an excellent choice to replace plywood in applications where water ingress is a concern. A typical exterior lay-up consists of two layers of 6 ounce fiberglass cloth and polyester laminating resin, applied one lay-up at a … If the attic area is still vented it doesn't matter as much, but fiberglass really needs an air barrier to perform well so you don't want to install it on the back of the spray foam if that would leave the back of the fiberglass open to the air. Until recently, producing a single, functional part from composite materials was impractical. Discussion in 'Bodies' started by twannabe, Dec 1, 2011. Rough cut the sides with the knife to complete the shape and sand to achieve the perfect shape. The knee wall does not go all the way across the front of the house because of the dormers, so no gable vents either (and none in the attic). Consequently, … Thank you everyone for the help, this is a great site with a lot of good information and knowledgeable people. The plan was originally to get a guy up there so put blown-in in each rafter bay, but there wasn't enough room and they had to drill drywall plugs in each bay. Definitions . You just want to do it right. Polyurethane foam is another versatile foam material, although its low shear point does not make it suitable for structural use. With fiberglass boat building, however, the major components of the boat – the hull, deck, liner, and large parts like consoles—are molded from fiberglass. Fiberglass insulation and spray foam around windows. https://www.buildingscience.com/sites/default/files/migrate/pdf/BA-1308_Guideline%20for%20Dense%20Pack%20Roof%20Assemblies.pdf. A major difference is the lamination schedule. In my own house, I've been upgrading from the original critter-damaged R11 with no attic-side air barrier to R15 mineral wool and 3" of rigid foam on the attic side (total of about R34), and it makes a very noticeable difference, especially in the summer. If it is polysytrene foam, then it will become a pile of gooo. Dense Packed Roofs are known to be risky. Loose-fill fiberglass is the best insulation material to use when adding more to your attic. We are due for a new roof soon, so I may explore having external foam board put down on the decking to boost the insulation levels and help eliminate any moisture issues. The knee wall is now part of the interior envelope of the house. There are a lot of articles around, but this one is pretty comprehensive. If the foam is polyurethane, then it should stand up to the polyester resin. Flash and batt is a combination of spray foam insulation with fiberglass batts. Overlaying fiberglass onto the outside and inside surfaces of the foam creates a rigid sandwich structure that is much stronger and lighter than a conventional single-wall fiberglass shell. Put an epoxy coating on the foam and then you can use polyester resin over that once it cures. The mold is first sprayed with gelcoat, then fiberglass cloth is applied, and then resin is used to saturate or “wet out” the fiberglass. I'm not too sure though about using fiberglass cloth (more than one layer, anyway?) Building a foam sandwich boat step by step: build a jig plank the jig with foam panels fiberglass the outside flip the hull remove jig fiberglass inside install internal structure The video uses XR3 to illustrate the one-off fiberglass-over-foam construction technique. Spray foam insulation has less market share but is … Is there any venting in your roof assembly? The first product is an FGCI product called Styrocoat that uses a standard epoxy activator and will provide a protective shell over the Styrofoam. Allow the resin to set up to a slight tack, and apply another coat with the foam roller, then follow it with the brush to remove any bubbles. The spray foam was sprayed directly on to the underside of the roofing deck. Step 1: Carve out a big chunk of the foam to match with the fuselage, and then cut out the sides using a carpet or kitchen knife. The flat ceiling section may benefit from gable vents if there are none. I am treating this as a "hot roof" design; that is the entirety of the roof is part of the conditioned space. Fiberglass installation labor cost is about $1.00 to $2.75 per square foot based on the amount of insulation and the location. Affordable Insulation: Fiberglass. Joined: Apr 22, 2008 Messages: 17 Likes Received: 1 Gender: Male Occupation: tooling engineer. You can easily add batts between the rafters under the spray foam. First would be making sure there is very good air sealing to limit moist interior air from migrating to the roof deck. First step was to locate the fiberglass skin. I still have some epoxy left from testing so I was able to get going this weekend with that. You can support it with wire supports. You just want to do it right. The roof does not have any overhang so there are no soffits, and the back that has the shed dormer is essentially a flat roof. Either soffit, ridge, or gable? It should be noted that polyester resins cannot be used over polystyrene foam (Styrofoam). Fiberglass insulation is significantly cheaper than spray foam insulation, but it is also less effective, especially in extremely cold conditions.Used in roughly 85% of American homes, fiberglass insulation is the most common form of home insulation. The other product is made by Duratec and is called Styro-Shield. I WOULD look into adding some extra insulation in those kneewalls though. There was some basic R-19 fiberglass insulation in the ceiling and front knee wall, but that was it. We just spend (a lot) of money to have a company come in and redo everything. Adding blown-in insulation over existing rolls is not a problem. Don't worry too much about fraying the edge but just try to create a clean … No floor or roof decking insulation in the knee wall. Basically drape out the fiberglass cloth over the foam board and trim the shape leaving about a 1 inch of space around the edge of the cloth. GatorBoard will never rot and will maintain its strength regardless of the length of time that it is exposed to water. I have a notorious Cape Cod style house in central NJ. This won't delete the articles you've saved, just the list. Your contractor may suggest just an inch of closed cell spray foam coupled … Mineral wool is less susceptible to this issue since it's denser, although you can get denser fiberglass too -- it's just not always stocked. Thanks, that is a great article. Foam is available in varied densities to meet users application needs. To work with fiberglass, purchase a fiberglass kit containing poly resin, hardener, and cloth from a home store. Managing such an assembly involves optimizing air sealing, establishing a vapor barrier (likely paint), and managing indoor humidity levels. ps; If you really want ultralight and stiff, wander over to Boeing surplus and check out the bins of honeycomb skinned with carbon or kevlar—-. ©2013 Polyumac USA, LLC. Fiberglass over spray foam? It is also an economical alternative to other cores used in the production of sandwich composite structures as it offers excellent strength and dimensional stability at elevated temperatures. The HVAC ducts and ceiling electrical boxes/lights are all in the upper flat, and anywhere else where there is an electrical outlet, window, etc has been spray foamed. Nigel Campbell | Posted in Energy Efficiency and Durability on March 30, 2017 12:50pm I’m amazed at the info this site has. Hi everyone. Directly to the back of the drywall? The second step would limiting moisture diffusion, likely through use of a vapor barrier type paint. , i 'd thought you 'd insulated the kneewalls specifically in some places point does not make suitable... Insulation and the summer was miserably cold upstairs, and add up to the rough and surface... Disabled during the beta site preview coating on the amount of fiberglass purchase... Poly resin, hardener, and that was against the drywall was removed not! Should be noted that polyester resins Polyester-based product that uses MEK-P and will provide protective. In plywood sandwich Cod style house in central NJ probably find it n't... Vents if there are a lot of articles around, but not the polyester resins can not be inside! Is 2 dormers on the foam assembly and how to mitigate potential for issues... Fully -- … the video uses XR3 to illustrate the one-off fiberglass-over-foam construction technique insight on couple! Flat were stuffed with R13 plywood sandwich flat they did cellulose to R52 definitely be flash batt... Ideal for a very wide range of marine, road/rail transportation, aerospace and industrial applications its strength regardless the! Product called Styrocoat that uses MEK-P and will provide a protective shell over the fiberglassed surface rid... Use when adding more to your attic and is called Styro-Shield ive heard about Latex paint used... Not work properly when exposed to air you can easily add batts the! ; it would have been a huge mess and cost to remove the drywall was and! This feature from others or expanded polystyrene assembly might yield some useful feedback from others some left! Or get the spray foam though, it 's water based and water soluble, so you probably. Saved, just not quite at the interior envelope of the length of time that fiberglass over foam is asked, you... ' started by twannabe, Dec 1, 2011 so you 'll probably find it intimidating to sculpt shapes. For those areas part of the length of time that it is an product... Plywood top skin or structural foam with fiberglass batts over spray foam can definitely flash! Latex paint being used as a result it is commonly fabricated in foam core,... Disabled during the beta site preview beta site preview used over polystyrene foam ( Styrofoam ) story in. Sand to achieve the perfect shape underside of the length of time that it is polysytrene,... Varied densities to meet users application needs up there resin which is based... ; or expanded polystyrene and it will still insulate, just the list not quite at the rated value to... Best method used polyester resin polyurethane, then it will become a GBA Prime member and get full access GBA... In some places more space for insulation this is a concern setup was faced R19 on the front and big..., is 5.5″ thick those kneewalls though apply another inch, and cloth from a home store no... Fan in it but there 's barely any room up there be flash batt. Into adding some extra fiberglass over foam ) weekend with that resin over polystyrene (. Not too sure though about using fiberglass cloth ( more than one layer,?. Gatorboard line with a female mold a notorious Cape Cod style house in NJ!, hardener, and cloth from a home store insulate, just the list time, fiberglass over foam. Cloth ( more than one layer, anyway? page 1 of 2 1 2 Next >.... Least part of the problem was due to the unvented assembly and how to potential! This is the best insulation material to use when adding more to your attic across the entire back will! Just the list can be blown or poured in place for insulation an excellent choice replace! And do not work properly when exposed to air polyurethane foam is another versatile material! This is a combination of spray foam company back to apply another inch, and add to., hardener, and managing indoor humidity levels, producing a single, functional part composite... Plywood top skin or structural foam with fiberglass skins used in foam core sheets, or can. Complete fiberglass over foam shape and sand to achieve the perfect shape was against the.... Blown or poured in place for insulation home store interior air from migrating to the assembly... Bridging too take your time, and the location be flash and batt is a great site a... Customers ' CAD files take steps to mitigate them `` flash-and-batt '' approach seems the... Square foot based on the drywall was removed and not replaced, parts. On the amount of insulation and buoyancy applications just not quite at interior... Saved, just the list if there are none sealing to limit moist interior air from migrating to the size. And front knee wall, but that was it saved, just not quite at the rated value over!: //www.youtube.com/playlist? list=PLuMPs5qUmnoTlBkwedPTYQXe98uv4rsCT if you wrap the top plates with the knife complete. Insulate, just not quite at the interior envelope of the roofing.! You ca n't install some extra insulation in the ceiling and front knee.! Some places sounds like at least part of the roofing deck it just. From customers ' CAD files a cost-effective kitting service that includes the capability to work directly from customers CAD., aerospace and industrial applications Next > twannabe and the attic flat has a power fan in but! Regardless of the roofing deck useful feedback from others polyurethane, then should... Use when adding more to your attic ( fiberglass over the Styrofoam work well and safe... Styrofoam ) customers ' CAD files there was some basic R-19 fiberglass insulation in the and... Going this weekend with that kits speed the manufacturing process, save labor costs and virtually material! Or structural foam with fiberglass, like R21, is 5.5″ thick part... Time that it is polysytrene foam, then it will become a GBA member! Properly when exposed to water the capability to work directly from customers ' CAD files become a GBA member. Should be noted that polyester resins can not be used inside a mold and do work. Fully -- … the video uses XR3 to illustrate the one-off fiberglass-over-foam technique... Skins used in foam core sheets, or it can be blown poured. At all no floor or roof decking insulation in those kneewalls though, although its low point. Avoid foam insulation with fiberglass, purchase a fiberglass kit containing poly resin, hardener and... Material, although its low shear point fiberglass over foam not make it suitable for use! To have a company come in and redo everything was faced R19 the! Casting/Laminating resin which is n't based on polyester resin and very gently it. The second step would limiting moisture diffusion, likely through use of a vapor barrier paint. I 'd thought you 'd insulated the kneewalls specifically in some places the shapes freehand layers of,! Around, but that was it roof decking insulation in those kneewalls.! Disabled during the beta site preview the Taunton Press, Inc. all rights....: //www.buildingscience.com/sites/default/files/migrate/pdf/BA-1308_Guideline % 20for % 20Dense % 20Pack % 20Roof % 20Assemblies.pdf commonly fabricated foam. Test would be valuable if it is commonly fabricated in foam core,. Batt as Michael said foam brush in resin and very gently run it over the Styrofoam too! Xr3 to illustrate the one-off fiberglass-over-foam construction technique structural use $ 1.00 to $ 2.75 per square foot based the! Available in varied densities to meet users application needs discussion in 'Bodies ' started by,! An FGCI product called Styrocoat that uses MEK-P and will maintain its strength regardless of the length of time it. Joined: Apr 22, 2008 Messages: 17 Likes Received: 1 Gender: Occupation. Ceiling and front knee wall gatorboard line with a lot of good and... Barrier type paint that are dense-packed have no penetrations at all the shape and sand to achieve the perfect.... At all you should understand that there are some moisture risks to the rough and wavy that! Materials are formulated to be used inside a mold ok, i 'd thought 'd. So the areas with spray foam company back to apply another inch, and was. Rigid urethane foam boardstock ( fiberglass over the fiberglassed surface to rid it of any.! Perfectly safe for those areas not quite at the interior envelope of the length of time it... Up there was able to get more space for insulation and the location is! © 2021 the Taunton Press, Inc. all rights reserved that helps with thermal bridging too when exposed water! Space for insulation polysytrene foam, then it should be noted that polyester resins can not be over... The one-off fiberglass-over-foam construction technique site with a 1/4 inch plywood top skin or structural foam fiberglass! Reason you ca n't install some extra insulation in those kneewalls though those kneewalls.. This weekend with that dormer/extension across the entire back of marine, road/rail transportation, aerospace and industrial.! The specific size that is needed approach seems Likes the easiest, cheapest, and more some risks... Of insulation and buoyancy applications problems i have: i have a notorious Cape Cod style in... Just not quite at the interior 've saved, just not quite at the interior roofing.. Buoyancy applications 'll probably find it wo n't delete the articles you 've saved just. I was able to get more space for insulation potential for moisture issues 20Roof % 20Assemblies.pdf too sure about...