Homasote: Worth it?

Thanks for doing this, Jeff.  And thanks for sharing.  I've never used Homasote but always wondered if it really made that big of a difference.  Nice work.

Jeff: You took a very logical approach to prove something to your father. I myself have always used Homosote, the trick is the screws should not go thru the homesite into the wood you lose any advantage in noise reduction as the noise transmits thru the screws into the wood. I have my entire 40x18 layout covered in homesite and was running a Post War Trainmaster and a set of Post War ABA's and standing next to the platform could carry on a conversation in a very low tone of voice.

Very nicely done. I would be interested to see the effect of mounting the track on cork roadbed that is attached directly to the plywood.

MELGAR

Very impressive study, I have been preaching the benefits of homasote for years. Remember that a sharp utility knife and straight edge works well for cutting and is dustless. I leave an 1/8 inch gap between sheets to allow for expansion and then after priming I fill the joints with Dap 230 caulk. I always use Kilz 2 primer which is water based and odorless. Then finish coat with anything you like.

Great study, I guess my investment in Homasote was worth it.

This is the table with the Homasote laid, the seam and screwheads sealed, ready for painting.

A coat of paint to seal it some and keep the dust down.

Laying track, the 1" screws go through the track, roadbed, and into the Homasote.

@RJT posted:

...the trick is the screws should not go thru the homesite into the wood you lose any advantage in noise reduction as the noise transmits thru the screws into the wood.

No, it does not! Did you read the OP’s post? In his post he said:

• Track screws that penetrated the homasote and went into the plywood base did not appear to result in measurable noise increases versus screws that only penetrated partway through homasote (this was contrary to my expectations based on several comments in this forum).

I agree. That is a myth that is dispelled by the poster's data.

MELGAR

The Gargraves screws don't reach my plywood anyway, so I don't run any risk.

I used homasote on almost all the tracked areas of my layout for roadbed with great results. However, I ran out towards the end of a layout expansion many years ago. I could not find homasote in my area readily available but I did find 4 x 8 sheets of a sound deadening board the same thickness that was brown in color and seemed to resemble homasote but was not quite as dense. I cannot recall the price but do recall that it was less expensive and worked well. So, I think the homasote and substitute were worth the added expense.

Do you believe you would find the same results with Fastrack or RealTrax ?

Why not just use Woodland Scenic’s foam roadbed and forgo the expense of homasote?

@superwarp1 posted:

Why not just use Woodland Scenic’s foam roadbed and forgo the expense of homasote?

We looked into various roadbed materials, but honestly the cost difference was negligible for a layout with the amount of track we've got.

A big downside to the foam was the requirement to glue it, and our layout is complex enough to require a ton of special cutting. If we wanted to change the layout, now we've got a bunch of foam we can't use.

@rpmcobra posted:

Do you believe you would find the same results with Fastrack or RealTrax ?

That is an excellent question. Same results? I suppose the original methodology the OP used to analyze might show some improvement using those brands of track, but likely not the "same". BTW, in my previous post I neglected to include that I use Atlas track.

@rpmcobra posted:

Do you believe you would find the same results with Fastrack or RealTrax ?

It's hard to say for sure. I have zero experience with any of the plastic roadbed track. I don't know what percentage of noise energy emanates from the surface it's mounted to versus the energy that actually emanates from the plastic cavity and molded roadbed surfaces.

I would, however, expect that whatever portion of energy that *does* move into the mounting surface would be reduced in a similar fashion to the tubular track. But if the percentage of that energy is low, then even with large reductions from the homasote the net reduction in overall noise would not be as much.

Yes. It's expensive but well worth the added expense when building a layout. It's also preference meaning you don't really need it to build the layout but it does knock down unwanted sound when used.

Solid rails also reduce noise. That's my preference.

Thank you for measuring this and posting it.  If you want additional noise reduction I recommend only gluing the homasote to the plywood.  Then attaching cork roadbed to the homasote with caulk.  And finally mount the track to the roadbed using 1inch track spikes.  I know you didn't measure much reduction with or without screws to the plywood, so it may not make much difference, but that's what I've had the best results with.

The cork on top of the homasote helps even more.  I don't have measured data, but I have built layouts with just plywood and just plywood and homasote and the plywood, homasote, and cork did the best job at limiting the noise.

Good luck!

@RJT: That's an impressive layout!  As for the screws, @Rich Melvin pointed out the part of data that I took that is at odds with the idea of long screws into the plywood negating the benefits of homasote.  This was, of course, only a limited experiment on a very small section of wood with a very specific configuration of framework below, so take that for what it's worth.  But I guess I wouldn't be too worried if I realized later on that some of my screws were getting into the plywood.

The Princess and the pea. No offense here to anyone.

@Jeff_the_Coaster_Guy posted:

We looked into various roadbed materials, but honestly the cost difference was negligible for a layout with the amount of track we've got.

A big downside to the foam was the requirement to glue it, and our layout is complex enough to require a ton of special cutting. If we wanted to change the layout, now we've got a bunch of foam we can't use.

Not to be difficult but BOTH statements are not true. I have some foam glued and some not. Difference = NONE! When I changed my layout I was expecting the foam that was glued to be worthless. To my surprise it came up easily and was still usable.

Just saying from experience.

Also I have heard people say you can not screw into foam. Again False. You just can not OVER TIGHTEN the screws. BUT if you do simply drop a small drop of glue (elmer's) or push a paper towel or tissue into the hole and re insert the screw and DON'T over tighten.

Again Been there done that so I know from experience.

Curtis

@RJT posted:

Jeff: You took a very logical approach to prove something to your father. I myself have always used Homosote, the trick is the screws should not go thru the homesite into the wood you lose any advantage in noise reduction as the noise transmits thru the screws into the wood. I have my entire 40x18 layout covered in homesite and was running a Post War Trainmaster and a set of Post War ABA's and standing next to the platform could carry on a conversation in a very low tone of voice.

JUST awesome, RJT. What an incredible amount of space with which to railroad! Looking forward to all futher posts, including running trains!

@Jeff_the_Coaster_Guy posted:

Dad and I are moving along on the layout that we've been planning the past few months, and we've completed the benchwork and moved on to the top side.

Dad's old layout was always just Lionel tubular track screwed right into a piece of plywood.  It's been like that since he was a kid, so I was trying to explain to him what homasote is and why members of this forum seem to recommend it as THE definitive surface to build on.  However, it presents a bit of additional labor, as well as another couple hundred dollars of investment.  Dad is skeptical of just about anything that he hasn't heard of before, so prior to giving me the OK to order 6 sheets of homasote and putting it on his Menards card, he wanted to see proof that it was going to be "worth it".

Although there are several advantages that forum members ascribe to homasote, the primary one (and the one dad is most interested in) is noise reduction.  Especially since, upon installing our first piece of plywood on our new benchwork, dad was not exactly thrilled with how loud a little PW engine on an impromptu oval really was.  If we were planning on running 3 trains simultaneously, this could get REALLY loud in our little concrete basement room.

So, we set off to make a definitive decision.  Was homasote, at a cost of about $300 installed, going to be worth the time and effort for the benefit of reduced noise?  Just how much noise reduction would we expect?  If it was one dB(a), it wouldn't even be perceptible, and dad would balk at the cost.  If it was three, then...maybe?  six or more?  That would be significant and maybe worth the expense.

Our experiment was simple.  We built a temporary oval of 027 tubular track on the bare 1/2" plywood screwed directly to our actual benchwork in the train room.  I downloaded a (paid) app for use with my Android that would suffice to measure sound pressure levels on the a-weighted spectrum (the spectrum that most affects human ears).  Even if it wasn't calibrated, we would still be able to collect *difference* data that would be worthwhile.  I installed an inexpensive microphone and hung the apparatus directly above the layout in a fixed location.  Then we collected noise levels over 30 to 60 seconds for several runs.  These runs included:

1. Collecting a "baseline" data set of ambient noise levels (no TV, no yelling kids, etc).
2. Running a PW Erie Alco engine alone around the loop at low, medium and high speeds
3. Attaching four cars to the engine and running the train around the loop at low, medium and high speeds
4. Substituting the PW Erie Alco with a modern Williams electronic F-Unit and running the train at several speeds
5. Removing the cars and running the Williams loco alone

We then took up the loop of track, installed and fastened a 1/2" piece of homasote using drywall screws through the homasote to the plywood, then reinstalled the exact same track oval using the exact same 1/2" #4 screws in the exact same holes as the ones we used to anchor the track to the plywood in the previous run.  This meant that the track was ONLY fastened to the homasote, since the screws were not long enough to penetrate through the plywood.  We then repeated the tests above with this homasote configuration.

Finally, to satisfy my curiosity and because of several comments I've seen here, I removed the 1/2" #4 screws and installed 3/4" #4 screws in the EXACT SAME holes that resulted in the track being secured through the homasote and into the plywood.

Photos of the experiment setup and relevant data below.  We fitted a logarithmic curve through the three data points and plotted the R^2 values next to them.  It's not a lot of data points, so the R^2 figures may not be as robust as we would like, but noise levels are measured on a log scale and these curves make perfect sense to us.

• The track was an oval of 14 piece, 133.25 inch nominal center rail circumference (nominal .1009 scale mi)
• "NS Engine" is my Williams Norfolk Southern 4270 "FA" Unit.
• "Erie" is my Lionel Postwar 2032 "A" Unit with solenoid E-reverser.
• The four cars used in the test were Lionel cars: Hormel boxcar GAH&Co 901, Reading Refrigerator car 16134, AT&SF Barrel car 356225, NYC caboose B&A 6920.  The barrel car and caboose had pickup rollers installed and functional.
• The software used to measure the noise was "Decibel X Pro" for Android by Skypaw Software
• The plywood was 1/2" 5-ply "A/C" with the track screwed to the "A" side.  The plywood was fastened to 1x4 benchwork using #8 drywall screws.
• The homasote was  4x4 ft, 1/2 in, sheet, attached diagonally to plywood with 1 5/8 in drywall screws, 8 around periphery, 2 in the center
• "Short screws" are #4x 1/2" wood screws to fasten track.  "Long Screws" are #4 x 3/4" wood screws.
• Microphone was mounted and remained stationary for the entire test 35 inches above the center of the turn furthest from the wall.  The raw data from the measurements clearly shows the train enter each curve with a slight change in SPL each time it straightens out.  The data was overall very repeatable and very clean.  Measurements Measurements are all Leq values in dB(a) at a sampling rate of 200 milliseconds.  Most runs lasted about 30 seconds, some longer, some shorter.

Photos of setups:

It's not a truly scientific setup, but was certainly good enough for our purposes, and I wanted to share my results with you all.  I've copied the relevant results to some images below, but the findings can be summarized as:

• PW loco was significantly louder than modern loco (no surprise)
• Speed is the single biggest factor in relative noise.  Faster=louder (again, no surprise)
• Homasote generally results in a 6 to 8 dB(a) reduction in noise for identical track / train / speed configurations. (Expected some reduction, but this is significant)
• Track screws that penetrated the homasote and went into the plywood base did not appear to result in measurable noise increases versus screws that only penetrated partway through homasote (this was contrary to my expectations based on several comments in this forum).

In these charts, "P" = "Plywood Only" and "H" = "Homasote".    Note that the "loudest" curve of any configuration on homasote was well below the "quietest" curve of any configuration on plywood.  .  There are a couple data sets we had to dump because there was an anomalous noise that affected the measurements (washer started on one, kids screaming, etc.).  So some only have one or two instead of three data points, but it really didn't end up making a difference.  So you can ignore the R^2 values where we have only one or two data points.

Here's all eight data sets together, with Homasote data sets highlighted:

Finally, here are data sets showing the long screws through to the plywood and the short screws in homasote only.  No discernable difference:

Most importantly, these tests matched our own "ear tests".  The homasote was a tremendous improvement in sound quality and loudness and general comfort being in the room with the equipment.  In practice, 3dB(a) is about the limit of noise level difference that the human ear can discern, so 8 dB(a) is a really noticeable drop in noise and discomfort.  So in conclusion, we're buying and installing the homasote, and would probably pay even more if it was more expensive than it is.  The result is about $37.50 per dB of noise reduction, and Dad and I both agree it's WELL worth it!

Jeff

Truly a fantastic piece of reporting and hard, mathmatically relevant work. You've convinced me; if I get my wish next year, I'll be starting a new layout, and instead of just pink/blue foam, I'll be using homosote!

I used homasote with good results.

And it has some scenic advantages as one can carve track side ditches or runoffs directly into it. I also use felt as the beginning of ground cover. It all seems to be quiet and scenics well. My two cents.

If one just wants to hear the train. This is an example.

Jeff, I agree with your results (impressive) and with what has been posted above. I installed Homasote on top of my decking, and the only sounds I hear are the trains gliding down the track. A cost effective way of cutting noise dramatically.

Andy

@Virginian65 posted:

Truly a fantastic piece of reporting and hard, mathmatically relevant work. You've convinced me; if I get my wish next year, I'll be starting a new layout, and instead of just pink/blue foam, I'll be using homosote!

Which leads to my question... Would "pink/blue foam" board be louder than homosote?? Seems to me the foam board would be as quiet or quieter..  I have used foam board on plywood in the past and pleased with it.. With that said, I used cork and/or foam roadbed under the track also.. I'm NOT trying to be confrontational!! I'm just curious!!

Would be interesting to see this same study using fastrack.

Great report.

I have used Homasote on several layouts and like the results.  Thank you Jeff for posting the information from your experiment.

Thanks Jeff. Confirms what we did. We added cork on the mainlines but we don’t see a lot of difference in sound and with the homasote didn’t care. It is quiet.

Seeing actual numbers was interesting.

One thing that some people often don’t know. Cut it with a flat (knife) blade and there is zero dust.

I always use Homasote.  My Dad had it on our basement layout.  I am 76 years old.  I glue the Homasote to the plywood with silicone caulk no screws.  Very pleased with results.  A pile of bricks until caulk is dry.

I put down cork roadbed on top of my Homasote solely for the purpose of getting a more prototype look of the raised roadbed.  I glue the cork with a minimum of carpenters glue and it peals up fine to make changes.  I have put down Homasote with glue or screws, and haven't noticed a difference.  I agree the reason to fasten down the track with screwed is to keep it from shifting side to side.  On my Ceiling Central RR I left track not fastened down because if working in a confined space, and the track shifts a bit on cork.  I built my Christmas layout on foam and the screws do hold if you don't tighten them to ring out the hole.

It's refreshing to see others that really take overthinking to new levels. Makes me feel like I really need to up my game on overthinking. I'm an amateur compared to the OP post! 

OU!

(Overthinker's Unite!)

Well done, OP (Jeff)!

We now have empirical data to support those of us that suffer from "Homasote Is Mandatory" thinking.

Andre

Impressive research Jeff!!   My bench work is open gird topped with 3/4 OSB.   I glued (construction adhesive) Homasote only in areas where the track would go (one way to manage the cost).   I painted (sealed) the Homasote before glueing on 1/4 cork road bed.    The main section of my layout is attached to the wall at one end, and is supported by six legs.   I added a 3/32 inch gasket rubber pad to the foot of each leg (probably not helpful but I had it, so I used it).    The open sections were later filled in with OSB and/or styrofoam as needed for scenery.   Track was anchored using GarGraves track screws.  No screws touched the OSB!  I am pleased with the sound control.    

In short, Homasote is well worth it and you can save expense by custom cutting it for track only.    PS: all my styrofoam and OSB was salvaged from construction dumpsters near our home.    I even got a job foreman to custom cut a section of OSB for me out of a full 4x8 sheet.  

Cheers, Dave

I removed all screws the next day after the adhesive set.

I also painted the cork roadbed.  

Layout today.

Sound sample:

@laming: LOL, not sure I'd categorize as "Overthinking" but maybe headed that direction.  75% of this entire project is just so I can catch up on missed time with my dad these last 6 years that I lived 1500 miles away from him, so just the quality time spent together arguing about where to locate the microphone compensates for any overthinking.

@darlander: Wow! Spectacular layout...we'll never get to that level of detail, but part of what has kept dad excited is sharing photos of y'alls layouts for inspiration. I was cautious about cutting the homasote just under track areas...partially because we've got a lot of track and switches, but also because of the amount of work and mess involved.

This is an awesome experiment and I guess I'm using homasote now haha great job!

Having built many layouts over a string of decades I can say from practical experience that Homasote is the only way I would go.  I have tried foam, ceiling tiles, sound board, etc upon customers specific request (demand)  but never really left the Homasote approach.

This is a message I posted about subject in an IO group

Rob Wachter Apr 5   #28367

Hi All, I did some simple sound decibel testing of Super O track and FasTrack on ¾” plywood and ½” Homasote. To understand fully the chart you need to read this entire message; sorry it’s long however it is necessary.

The first time I set up two composite folding tables and placed the ply and Homasote on them. The tables had a piece of thick paper (1/32” gray Homasote like recycled paper) similar to this

https://www.lowes.com/pd/Ram-B...t-Drop-Cloth/4514588

placed between the ply and table top. I placed the track directly to the ply and Homasote then used Styrofoam under the track then rug and finally screw the track directly into the bases.

The second time around I placed the track on the bases which were support by saw horse to allow any sound to be transmitted from the bottom of the ply or Homasote. The bases were clamp to the plastic saw horses.

I have attached a jpg of the Excel table listing the values and also the Excel sheet and also photos of the base configurations. The small numbers to the left are the lowest decibels recorded and the small numbers to the right are the highest decibel numbers recorded. I only posted those numbers for the plastic table testing.

I used my Android 7 photo with an App from Google play called Sound Meter. You have to hold it in portrait style to see the average numbers in free mode because a small ad bar at the bottom is present. The App download is easy and simple to use.  I stood about 2 feet away from the circle of track and placed the phone about 6 to 8 inches away from my face at a small downward angle like I was taking a photo of the track.  You have to hit the reset button top right to get accurate readings in the App. It did take many hours to do this.

The trains I used were a 2046 steam engine (runs like a clock), GP9 1961 engine, Lionel set # 6-30189 LIRR train set with can motor, some postwar cars, #50 Gang car and a MTH hand car. All traveled the same way and in order. The voltage was set at 14 volts on the ZW which actually read 15.3 volts; nothing was connected to the ZW other than the track being tested.

The 2046 (without tender or cars) speed had to be reduced to 12 volts due to the fact it would leave the track. TheGP9 had to have its speed increased to 16 volts when the cars were added to bring it to the average speed of the other trains.

The buzz from the GP9 read 60; decreased to 58 when placed on rug. The buzz from the 2046 was 50 for all testing. LIRR had no buzz from e-unit.  Whistle measured a high of 82 from the 2046 tender. I used the horse corral to measure decimal reading for each type base; it came in at 11 volts between 70 and 72 decimals for the horse to move up the ramp nicely. I did this for the four different configurations of the two materials and table/ saw horse platforms.

My Dewalt 20 volt battery drill measured 75 decibels at full speed and my doorbell measure a max of 82. HGTV shows normal speech was about 65 at a high point.

The differences from ply to Homasote were small however noticeably when the track was screwed in the base. One other thing that occurred was that when I was taking the readings on the saw horses the average number I posted had more highs on the plywood than the Homasote. The Homasote had spikes of only 3 to 4 were the ply had spikes of 4 to 6 while on the saw horses. The FasTrack and plywood combo on the saw horses was the highest with spikes as much as 10 decimal over the average. The high and lows for the plastic table are posted in the Excel file and jpg. Sound Meter displays an average reading. The average takes into account the time a reading is displayed. So the average is closer to the bottom number then the top.

The smallest average numbers were observed when Super O was just laid on top of the Homasote; 3 for the lower end and 3 for the top spike while the LIRR 1550 and/or cars were used.

The biggest change in spike volume would be when the rug was placed under the FasTrack.

All and all the Homasote did not do as good as I would have thought.  The top of the Homasote was painted and is 12 and 1/2 years old. Maybe if the Homasote was new then the decimal values would have been less. When I build the new layout and use fresh Homasote I’ll continue with the readings.

The Christmas layout was built in 1993 with a ¾ inch plywood platform base with ½ Homasote as a track base. It has Tinplate Gargraves track which is ballasted with a stone gravel form Woodland Scenic. The same ZW was used with the same voltages used for the trains which were used for the track on the other platforms.

One other observation was that the Super O track had a steady speed thru-out its circle whereas the FasTrack would speed up very slightly at the wire connection. The FasTrack was new out of the box. Each track had only one power and ground connection. The Super O was mostly the black notched type (Type I mold D) with one or two black semi-circle track (Type II mold D).

Please see attached photos. The Super O and Fast track were moved as a complete circle for each table change.  I used the aftermarket buss clips that are not magnetic. I purposely added to the Super O circle one curve track which had the center rail raised a little at the end to see how it reacted. I posted a photo of the amount of lift that clip had. It stayed that way throughout the testing. Since the trains always went around in a clockwise direction it posed no problem. Of course the Super O circle was not a perfect 36” center to center circle; measured 35 and 3/4 to 36 and 1/8 across the diameter.

It was fun to do and hope some of you can post decimal readings of your layout. Maybe this will help members who are planning a new layout? It was a great excuse to run some trains. Regards Rob

@superorob posted:

This is a message I posted about subject in an IO group

Rob Wachter Apr 5   #28367

Hi All, I did some simple sound decibel testing of Super O track and FasTrack on ¾” plywood and ½” Homasote. To understand fully the chart you need to read this entire message; sorry it’s long however it is necessary.

Interesting results, Rob. As some have suspected earlier, the Fastrack and Plastic-based tracks might respond differently, since the way they emanate sound is most certainly functionally different.  Although your experiment wasn't set up the same as mine, if we ignore the actual dB values (were they a-weighted?) and just look at the deltas only, the deltas for the fastrack on homasote and plywood aren't as much as what I found with tubular track.

Come to think of it, I have a circle of MTH Realtrax that came with one of my early RTR sets...maybe I will take a few more measurements with the RealTrax on my table for comparison.

Jeff there are many variables to take into account. However rug under the track no matter what the track is, is by far the quietest.  A  plus10 reading gives about a perceived doubling of volume to our human ears as I understand it. So if you have an average that is plus 5 higher than the other reading and also has a plus 5 higher on the high end of that reading it registers much louder to our ears. I run mostly postwar trains so they are loud to begin with, however to my old ears Super O on Homasote is quiet enough for me and honestly it looks great with or without ballast. Regards Rob W.

Yes, I think it is helpful in reducing sound