I've been doing a lot of research on all the trailers out there Timberwood and Iron Eagle and a few others by far Iron Eagle is the best one I've seen they really thought of everything this is a trailer I will go with by far they've done the best job in designing
We were so lucky to come across them on our first trip to Portland (to the tiny house hotel), and now have this relationship with them. Obviously we agree that they have the best design! If you do end up buying one, make sure to ask for the Tiny Nest discount! it helps support us!
Tiny Nest of course that's what I'm going to do yes I am planning to buy one but first I got to pay off my credit debt and then I'll buy it which I'll be out of that in no time
Would you guys recommend a double bottom plate here for your wall framing? If you only use a single bottom plate, the 1" foam + the 3/4" subfloor would be above the bottom plate. Would that be an issue? I would imagine when you put up your interior walls you will want to be able to nail the bottom of them into something (that 2nd bottom plate) Hopefully, I am understanding the video correctly. Thanks again Tiny Nest! -T
This is a great detail to explore, and one that still needs to mature as tiny house building techniques are tested... in the interest of getting as much insulation as possible, it might be good to have a single bottom/sil plate in terms of the wall-framing, but then add horizontal blocking that acts as backing for fastening into... possibly even on-edge (twisted 90-degrees) so that you could get insulation in behind it (on the exterior side of the wall-cavity). This is just a thought, and I don't know if it would be extra hassle vs how much insulation value is possible to achieve compared to a solid double-plate... but I encourage you to play with some ideas and let us know what you end up doing for your build!
So that little flange extrusion all around the trailer has been rated and can reliably support the weight of the walls and roof? And the foam insulation between the trailer and the ledger doesn't compromise any structural strength? Thanks for the help :)
This is a common question for which we've shared our understanding in several comment replies (check our other Iron Eagle videos). The short-version is: the load that bears down on walls is distributed around the entire perimeter, and if take the total expected weight of that load for a given project, and then divide it by the linear length of the perimeter, you'll end up with a number that doesn't seem like much weight at all (considering it would have to snap steel welds). NOTE that we are not engineers and don't really have experience with metal-work, so we recommend contacting Iron Eagle directly for an accurate and official answer.
Quick comment that I've run into playing with your models in SketchUp and gets shown on this video is the 2x6 framing when set on top of the 1" foam doesn't come flush with the inch of foam on the flanges. It's just a bit lower by about 5/16". Curious how Derin solves this issue, if he just ignores it and squishes the foam down when the subfloor ply goes on or something else.
If you wanted it to be flush, you could seek out a thinner foam, or rip down the 2x6s... or MAYBE hammer down and crush the foam enough to make it flush?... but Derin is actually suggesting that you should have the framing proud of the trailer deck and then lay more insulation down on the deck/flange to shim it up flush, making your framing and subfloor completely separated from the trailer.
Awesome, thanks for the speedy reply! I wonder if running some threaded rods through the length of the cross joists would help them stay square and prevent sagging. Kind of like the vertical walls on the flange but horizontal and not hooking into the metal.
Hm, I'm not sure rods like that would have the effect you're imagining... and I don't think that sagging joists is much of concern... but if you were worried, it might be better to lay a strip of material (metal maybe) long the length of the trailer in the middle, so it would rest on the trailer cross-members and the joists could then rest on that.. if that makes sense!
I'm confused by the use of Derin's LedgerLok screws for the connection of the floor framing to the trailer. I looked at the LedgerLok website and these seem to be like a Lag bolt that is used to make wood connections. How does this work with the steel frame? Thanks in advance for clarification. Great website by the way. I have purchased the Iron Eagle trailer and about to start the build.
The trailer has holes pre-drilled (plus you can drill your own in different spots if needed) so the idea would be to use washers and come at the joists from outside the trailer frame (through the holes), so that as you tighten, you are pulling the joist tight up against the layer of insulation and securing it in place... it's a bit hard to explain in words... we might try to make a new demonstration video some time in the future.
I believe the pre-punched holes are 30-inches apart, but you could ask for a different spacing if needed. Iron Eagle tends to be very accommodating to special requests.
I really like this idea, but if you are raising everything up by and inch except your 2x4 sill plate, then you won't have a good connection of your interior sheathing (whatever that might be, I'm going to use 1/4 sanded plywood) to the sill plate. Can you explain to me how that might work? Thank you for the videos and all the information. I have not started my project yet and am not a builder.
You can always double-up your bottom-plate (two 2x4s laid flat). We're also really interested in finding a material or technique to shim up the bottom-plate onto an insulating material to give even more thermal break from the trailer, but without compromising the way the wall rests its weight on the trailer...
I too was interested in finding a shim technique. I ended up using Trex decking under the 2x4 sill plate with xps foam under the subfloor. The Trex is a very rigid and waterproof material. It should create a decent thermal break, but if nothing else I am not concerned about it absorbing moisture due to condensation as I was the 2x4. Also, since I used a flat deck trailer for our build as I didn't have access to an Iron Eagle Trailer it was nice that both materials were 1" thick so they ended up flushing out. Thanks Derin for this informative video, and for enlightening me on the issues of using the ubiquitous sill gasket!
compromising structure with rigged insulation foam (long term) is an obvious problem to avoid .. the desire for a warm floor is hard to resist, but (as were now beyond the basics) the issue of foam insulation deflection has been addressed. Take a look at Marmox THERMOBLOCK® insulation panels as a more stable thermal break with enhanced structral stability
Those look super cool. I had been thinking about the need for insulation that can also support the weight so that you CAN place it directly under bottom-plates, the floor, etc... but this particular product looks to be designed for use with concrete and is glued down with mortar, and I am not a fan of such rigid or brittle material in a tiny house... the idea is excellent though.
glue/mastic is generally used, but there is nothing stopping you from pin/nails/screws or both .. in fact many above attachments would need to sink into subfloor or structural members to be firmly afixed
when you talk to IE people, since they now do a three axle trailer, they might want to add a 32' footer to their catalog .. also ask them about an outrigger option (bolt on, not factory installed), so TH buyers can get to 10' wide TH foundations on any length trailer?
Interesting idea about the bolt-on extension... I'll definitely keep that in mind. I think it would take quite a bit of development, but could be something to look into in the future :)
Since you're likely to build/frame a box around the wheel-wells, you'd end up with a square shape anyway. The fender itself is on the cold-side, so you just need to have a layer of insulation layered against the warm/interior surface. You could also spray-foam the resulting void if you really want to seal it up to prevent insects and whatnot from finding their way in.
great video. Thanks for the tips. One question. Why do you run the sheathing on the inside of the wheel well flange instead of outside of the flange? Can't you achieve a similar shear strength by nailing the plywood a couple inches up from the bottom of the wall framing (or in the case around the wheel well a couple inches up from the bottom of the header)?
On our own Tiny Nest, we actually brought our sheathing down in-front of the fender-flashing like you're describing... but it was admittedly a bit awkward because it doesn't sit nicely (being shimmed out by the flashing). It also meant that we are overhanging the trailer by 1/2" more than if we kept the sheathing inside... my initial logic lead me to want to shingle it this way (and so we did), but when you think about the fact that: once water is running down the face of your sheathing, you're already in trouble, then it makes more sense to use the house-wrap as the shingling element (because it's designed to repel water that has gotten behind your siding). Derin also commented that with our method, the bottom exposed edge of the plywood (that we overlapped the flashing) is vulnerable to wicking moisture... we did leave a decent gap so that it's up off the fender itself, but it's a valid point, and is not an issue when the sheathing is kept behind the flashing. TL;DR: I also initially resisted this idea, but now agree with Derin that it's a better installation.
I disagree with the premise that your overall floor R rating is the lowest value found at any one point. It would be an average proportional to the space and methods used. The bigger area of concern is ventilation efficiency and window / door openings in my estimation. With the best windows available being in the R-5 range. It's clear you guys do nice work and the iron eagle's are the standard.
You are right about the average. Derin talked to me about having done more in-depth research and calculations and had found that the average was in fact drastically affected by having even small sections bridged to the trailer... I can't speak to the details myself, but I believe it is a weighted average of some kind, not proportional to the R values on each square foot added up and then divided... and this would make sense because if you have a spot where heat can escape easily, you will loose quite a bit there, even though the rest of the area is well-insulated... this is the same principal that you brought up about ventilation/windows... if you have a weak-spot anywhere, it will have a significant impact on the heat-retention of the envelope as a whole.
Soving this is Derin with Shelter Wise, it was a whole floor R-value calculation that I did. To do this you have to figure out the U-value of each material and its percent coverage of the floor area to do the calculation, super nerdy. The trailer poses the biggest hurdle being that its a 2000lb+ conductor. In most tiny homes (20-28ft) about 25-30% of the subfloor is in direct contact with the trailer, think of it as a negative R-Value, its actually sucks heat out of your house as well as makes for a great place for hot humid air to condensate on at your sill plates:) Some trailers with cross members at the rail height might even have 50% in direct contact with the subfloor. Lastly the pink sill sealer that people use to create a thermal break actually just compresses and has no R-value, I learned that the hard way:) And yes ventilation is very important, by far the most important!
The idea here is to avoid placing any real weight onto the insulation. The floor structure is secured to the sides of the trailer (see this video: ua-cam.com/video/dmMqREa0lWY/v-deo.html), you can't rest the walls (bottom-plate) directly on any insulation, and you have to be mindful of putting any underneath the subfloor where any furniture or foot-traffic might be.
rigid insulation is placed under the concrete floors of commercial and residential buildings all the time. But those slabs do not usually extend under the walls. I think that it is an uneven and concentrated load bearing on foam (i.e. at the trailer frame but not under the rest of the floor) that causes an issue such as broken caulking or flashing or binding windows or doors. Furthermore, it is the appearance of structural weakness.... such as a "bouncy" or spongy floor that can be disconcerting if not truly diastrous. So it's best to avoid it.
good question, the insulation should not go under the exterior wall sill plate if that is what you asking, regarding the floor, it has direct connection to a 2x6 floor framing system which is ledgered into the trailer framing with an R5 thermal break.
good to see some "building science" by a tiny houser :)
Tiny houses are a great opportunity to maximize the sciencing!
I've been doing a lot of research on all the trailers out there Timberwood and Iron Eagle and a few others by far Iron Eagle is the best one I've seen they really thought of everything this is a trailer I will go with by far they've done the best job in designing
We were so lucky to come across them on our first trip to Portland (to the tiny house hotel), and now have this relationship with them. Obviously we agree that they have the best design! If you do end up buying one, make sure to ask for the Tiny Nest discount! it helps support us!
Tiny Nest of course that's what I'm going to do yes I am planning to buy one but first I got to pay off my credit debt and then I'll buy it which I'll be out of that in no time
Great video jake
It's all Derin in this one ;D
Nice detail.
Would you guys recommend a double bottom plate here for your wall framing? If you only use a single bottom plate, the 1" foam + the 3/4" subfloor would be above the bottom plate. Would that be an issue? I would imagine when you put up your interior walls you will want to be able to nail the bottom of them into something (that 2nd bottom plate)
Hopefully, I am understanding the video correctly.
Thanks again Tiny Nest!
-T
This is a great detail to explore, and one that still needs to mature as tiny house building techniques are tested... in the interest of getting as much insulation as possible, it might be good to have a single bottom/sil plate in terms of the wall-framing, but then add horizontal blocking that acts as backing for fastening into... possibly even on-edge (twisted 90-degrees) so that you could get insulation in behind it (on the exterior side of the wall-cavity).
This is just a thought, and I don't know if it would be extra hassle vs how much insulation value is possible to achieve compared to a solid double-plate... but I encourage you to play with some ideas and let us know what you end up doing for your build!
Tiny Nest thanks for the response. We start our build here soon (assuming the weather cooperates). I will let you know what I end up going with
So that little flange extrusion all around the trailer has been rated and can reliably support the weight of the walls and roof? And the foam insulation between the trailer and the ledger doesn't compromise any structural strength? Thanks for the help :)
This is a common question for which we've shared our understanding in several comment replies (check our other Iron Eagle videos). The short-version is: the load that bears down on walls is distributed around the entire perimeter, and if take the total expected weight of that load for a given project, and then divide it by the linear length of the perimeter, you'll end up with a number that doesn't seem like much weight at all (considering it would have to snap steel welds).
NOTE that we are not engineers and don't really have experience with metal-work, so we recommend contacting Iron Eagle directly for an accurate and official answer.
Quick comment that I've run into playing with your models in SketchUp and gets shown on this video is the 2x6 framing when set on top of the 1" foam doesn't come flush with the inch of foam on the flanges. It's just a bit lower by about 5/16". Curious how Derin solves this issue, if he just ignores it and squishes the foam down when the subfloor ply goes on or something else.
If you wanted it to be flush, you could seek out a thinner foam, or rip down the 2x6s... or MAYBE hammer down and crush the foam enough to make it flush?... but Derin is actually suggesting that you should have the framing proud of the trailer deck and then lay more insulation down on the deck/flange to shim it up flush, making your framing and subfloor completely separated from the trailer.
Awesome, thanks for the speedy reply! I wonder if running some threaded rods through the length of the cross joists would help them stay square and prevent sagging. Kind of like the vertical walls on the flange but horizontal and not hooking into the metal.
Hm, I'm not sure rods like that would have the effect you're imagining... and I don't think that sagging joists is much of concern... but if you were worried, it might be better to lay a strip of material (metal maybe) long the length of the trailer in the middle, so it would rest on the trailer cross-members and the joists could then rest on that.. if that makes sense!
I'm confused by the use of Derin's LedgerLok screws for the connection of the floor framing to the trailer. I looked at the LedgerLok website and these seem to be like a Lag bolt that is used to make wood connections. How does this work with the steel frame? Thanks in advance for clarification. Great website by the way. I have purchased the Iron Eagle trailer and about to start the build.
The trailer has holes pre-drilled (plus you can drill your own in different spots if needed) so the idea would be to use washers and come at the joists from outside the trailer frame (through the holes), so that as you tighten, you are pulling the joist tight up against the layer of insulation and securing it in place... it's a bit hard to explain in words... we might try to make a new demonstration video some time in the future.
How many inches apart would you suggest for the holes? Thank you!
I believe the pre-punched holes are 30-inches apart, but you could ask for a different spacing if needed. Iron Eagle tends to be very accommodating to special requests.
I really like this idea, but if you are raising everything up by and inch except your 2x4 sill plate, then you won't have a good connection of your interior sheathing (whatever that might be, I'm going to use 1/4 sanded plywood) to the sill plate. Can you explain to me how that might work? Thank you for the videos and all the information. I have not started my project yet and am not a builder.
You can always double-up your bottom-plate (two 2x4s laid flat). We're also really interested in finding a material or technique to shim up the bottom-plate onto an insulating material to give even more thermal break from the trailer, but without compromising the way the wall rests its weight on the trailer...
I too was interested in finding a shim technique. I ended up using Trex decking under the 2x4 sill plate with xps foam under the subfloor. The Trex is a very rigid and waterproof material. It should create a decent thermal break, but if nothing else I am not concerned about it absorbing moisture due to condensation as I was the 2x4. Also, since I used a flat deck trailer for our build as I didn't have access to an Iron Eagle Trailer it was nice that both materials were 1" thick so they ended up flushing out. Thanks Derin for this informative video, and for enlightening me on the issues of using the ubiquitous sill gasket!
compromising structure with rigged insulation foam (long term) is an obvious problem to avoid .. the desire for a warm floor is hard to resist, but (as were now beyond the basics) the issue of foam insulation deflection has been addressed. Take a look at Marmox THERMOBLOCK® insulation panels as a more stable thermal break with enhanced structral stability
Those look super cool. I had been thinking about the need for insulation that can also support the weight so that you CAN place it directly under bottom-plates, the floor, etc... but this particular product looks to be designed for use with concrete and is glued down with mortar, and I am not a fan of such rigid or brittle material in a tiny house... the idea is excellent though.
glue/mastic is generally used, but there is nothing stopping you from pin/nails/screws or both .. in fact many above attachments would need to sink into subfloor or structural members to be firmly afixed
when you talk to IE people, since they now do a three axle trailer, they might want to add a 32' footer to their catalog .. also ask them about an outrigger option (bolt on, not factory installed), so TH buyers can get to 10' wide TH foundations on any length trailer?
Interesting idea about the bolt-on extension... I'll definitely keep that in mind. I think it would take quite a bit of development, but could be something to look into in the future :)
That foam looks a bit rigid. How can it be laid flush on the curve of the wheel well?
Since you're likely to build/frame a box around the wheel-wells, you'd end up with a square shape anyway. The fender itself is on the cold-side, so you just need to have a layer of insulation layered against the warm/interior surface. You could also spray-foam the resulting void if you really want to seal it up to prevent insects and whatnot from finding their way in.
great video. Thanks for the tips. One question. Why do you run the sheathing on the inside of the wheel well flange instead of outside of the flange? Can't you achieve a similar shear strength by nailing the plywood a couple inches up from the bottom of the wall framing (or in the case around the wheel well a couple inches up from the bottom of the header)?
On our own Tiny Nest, we actually brought our sheathing down in-front of the fender-flashing like you're describing... but it was admittedly a bit awkward because it doesn't sit nicely (being shimmed out by the flashing). It also meant that we are overhanging the trailer by 1/2" more than if we kept the sheathing inside... my initial logic lead me to want to shingle it this way (and so we did), but when you think about the fact that: once water is running down the face of your sheathing, you're already in trouble, then it makes more sense to use the house-wrap as the shingling element (because it's designed to repel water that has gotten behind your siding). Derin also commented that with our method, the bottom exposed edge of the plywood (that we overlapped the flashing) is vulnerable to wicking moisture... we did leave a decent gap so that it's up off the fender itself, but it's a valid point, and is not an issue when the sheathing is kept behind the flashing.
TL;DR: I also initially resisted this idea, but now agree with Derin that it's a better installation.
Thanks for the response. The input and conversation here is great!
I disagree with the premise that your overall floor R rating is the lowest value found at any one point. It would be an average proportional to the space and methods used. The bigger area of concern is ventilation efficiency and window / door openings in my estimation. With the best windows available being in the R-5 range. It's clear you guys do nice work and the iron eagle's are the standard.
You are right about the average. Derin talked to me about having done more in-depth research and calculations and had found that the average was in fact drastically affected by having even small sections bridged to the trailer... I can't speak to the details myself, but I believe it is a weighted average of some kind, not proportional to the R values on each square foot added up and then divided... and this would make sense because if you have a spot where heat can escape easily, you will loose quite a bit there, even though the rest of the area is well-insulated... this is the same principal that you brought up about ventilation/windows... if you have a weak-spot anywhere, it will have a significant impact on the heat-retention of the envelope as a whole.
Soving this is Derin with Shelter Wise, it was a whole floor R-value calculation that I did. To do this you have to figure out the U-value of each material and its percent coverage of the floor area to do the calculation, super nerdy. The trailer poses the biggest hurdle being that its a 2000lb+ conductor. In most tiny homes (20-28ft) about 25-30% of the subfloor is in direct contact with the trailer, think of it as a negative R-Value, its actually sucks heat out of your house as well as makes for a great place for hot humid air to condensate on at your sill plates:) Some trailers with cross members at the rail height might even have 50% in direct contact with the subfloor. Lastly the pink sill sealer that people use to create a thermal break actually just compresses and has no R-value, I learned that the hard way:) And yes ventilation is very important, by far the most important!
I will ask the obvious question.............will the solid insulation break down or compress from the weight of the structure over time?
The idea here is to avoid placing any real weight onto the insulation. The floor structure is secured to the sides of the trailer (see this video: ua-cam.com/video/dmMqREa0lWY/v-deo.html), you can't rest the walls (bottom-plate) directly on any insulation, and you have to be mindful of putting any underneath the subfloor where any furniture or foot-traffic might be.
rigid insulation is placed under the concrete floors of commercial and residential buildings all the time. But those slabs do not usually extend under the walls. I think that it is an uneven and concentrated load bearing on foam (i.e. at the trailer frame but not under the rest of the floor) that causes an issue such as broken caulking or flashing or binding windows or doors. Furthermore, it is the appearance of structural weakness.... such as a "bouncy" or spongy floor that can be disconcerting if not truly diastrous. So it's best to avoid it.
good question, the insulation should not go under the exterior wall sill plate if that is what you asking, regarding the floor, it has direct connection to a 2x6 floor framing system which is ledgered into the trailer framing with an R5 thermal break.
Isn't that the "hot guy", who everyone went on about, from the other video? Lol!
lol... the one and only!
But what if I like getting water inside my tiny house?
Tiny indoor pool?
Precisely! Where are the toxic mold spores supposed to take a bath? You have to think ahead about these things...
This is a bit confusing... :-/
Any part in particular?