Soundown Carpet Underlayment Installation

For years I've been considering, researching, budgeting and planning to install a sound attenuating carpet pad under my salon carpet. Something else always seemed to take higher priority but I finally got it completed this week. Here's the tale...

First, a huge shout-out to Keysdisease/Steve who provided me with great information, samples and advice about the Soundown products and relayed his own experience in his Mainship 34. He helped me find the right pad thickness and vinyl weight for my boat. (I picked the 1/2 inch foam-1 Lb/Sq Ft vinyl.) It's always nice doing business with a fellow TFer. Thanks, Steve!

I pulled the rugs and carpet to expose the old felt pad. I don't know if the pad's original but it sure looked it! Off with the pad to expose the unpainted facepalm floor repair after fuel tank removal by the PO. After removing the 100+ staples and about a lb of sand/dirt with a vacuum, it was time to cut and fit.

The pad just floats on the floor and one hatch without attachment except for the other hatch with a table base installed. The 54 inch width was just about perfect for covering about 85% of my floor dimensions. I cut the hatches with a 2" overhang to mitigate noise transfer through the gaps. The material was easy to cut with a utility knife and a good shear or scissors.

The 1/2 inch foam pad keeps it from shifting and the mass loaded vinyl soundproofing layer is smooth and comfortable to walk on. No issues with the carpet moving on top of the vinyl either. It all feels very soft but stationary.

I put it all back together and it looks and feels great! It was too windy to go out today but at high idle in the slip, the sound level is noticeably improved. I did a sound test before the installation and I'll do a new sound test the next time I'm enroute and post comparison readings here.

As I was lying in bed last night reminiscing fondly about my handiwork for the day, I pondered the remnants. They were roughly 2 ft wide and 7-8 ft long total. Could they fit under the fwd 'hall' or passageway carpet? This morning I laid the carpet on the dock and figured out that if I started the coverage fwd of the ladder steps (no pad under the ladder), I could cover the entire space completely! Perfect! That area has never had carpet pad and feels fantastic underfoot now that it's there! In my book, that's a free bonus room!

I'll post more when I get the sound tests completed.

I put it in a previous boat and liked it. Yes it was very easy to install.

Nice work. This is something I am interested in doing also. I will be watching for your data and impressions...thanks for sharing!

Nice work. Looks very professional.
Did you take some sound readings before with a dB meter? Interested in hearing the before and after results.

FOG said:

Nice work. Looks very professional.
Did you take some sound readings before with a dB meter? Interested in hearing the before and after results.

Click to expand...

I have a phone app called Advanced Spectrum Analyzer Pro that records a screenshot of the frequency spectrum. Yes, I took a "before" measurement at cruise power.

I'll post some comparison pics soon.

Advanced Spectrum Analyzer Pro

I used soundown material on my generator enclosure and floor and it made a big difference. Also used Steve and he was a huge help.

Fly thanks for sharing great work

Question are you happy with the 2" overlap now that it is in or would you do different?, I know you have not had much time to use the hatch with it in

It does work well, but with our launch , moving it after lifting the carpet to check the engine for the next days run becomes a drill.

But the quiet is a delight.

I was worried about that, too, Fred. That's one reason I went with the 1 lb/sf vinyl instead of 2 lb/sf and cut out the hatch covers to be lifted separately. My top hatches only get opened for engine maintenance or large ER jobs. Simple engine and fluid checks and top-offs are done with access through the fwd ER door (below the steps) or the aft ER lazarette in the cockpit.

Alan, I'll let you know about the 2 inch overlap, but it's what Steve recommended. It's a very tight fit so I seriously doubt I'd notice the difference from a solid sheet vs one with cut hatches.

FlyWright said:

I was worried about that, too, Fred. That's one reason I went with the 1 lb/sf vinyl instead of 2 lb/sf and cut out the hatch covers to be lifted separately. My top hatches only get opened for engine maintenance or large ER jobs. Simple engine and fluid checks and top-offs are done with access through the fwd ER door (below the steps) or the aft ER lazarette in the cockpit.

Alan, I'll let you know about the 2 inch overlap, but it's what Steve recommended. It's a very tight fit so I seriously doubt I'd notice the difference from a solid sheet vs one with cut hatches.

Click to expand...

Thanks look forward to hearing I am sure his recommendation it is going to be perfect

FlyWright said:

The pad just floats on the floor and one hatch without attachment except for the other hatch with a table base installed. The 54 inch width was just about perfect for covering about 85% of my floor dimensions. I cut the hatches with a 2" overhang to mitigate noise transfer through the gaps.

Click to expand...

Very timely, thanks for posting. We're just now getting ready for a re-carpet job... and in fact we just selected the color from our samples today.

So your real (over-) carpet isn't tacked down around the edges, etc.?

siestakey said:

Question are you happy with the 2" overlap now that it is in or would you do different?, I know you have not had much time to use the hatch with it in

Click to expand...

FlyWright said:

I was worried about that, too, Fred. That's one reason I went with the 1 lb/sf vinyl instead of 2 lb/sf and cut out the hatch covers to be lifted separately. My top hatches only get opened for engine maintenance or large ER jobs.

Click to expand...

And your engine hatches are not "wrapped"?

How much noise could there be from around the hatch seams without the 2" overlap

-Chris

Right...everything floats and stays stationary. My carpet has floated on a felt pad for 11 years that I've owned it without incident. Makes it easy to pick up to access the hatches.

Maybe Steve can answer the question about noise from the hatch seams without overlap. I suppose every boat is different. My hatches are not tight fitting so the overhang was critical, IMO. Tough to quantify the difference without testing, though.

FlyWright said:

.... a huge shout-out to Keysdisease/Steve who provided me with great information, samples and advice about the Soundown products... It's always nice doing business with a fellow TFer. Thanks, Steve...

Click to expand...

I’ll second that. When we redid the engine room Steve was an invaluable resource.

Nice job Al.

We had a previous boat recarpeted. We used the Soundown 2# 1/2” underlayment. I had them bind the edges around the hatches and then sew 2” velcro on the bottom of the carpet facing up with 1” sticking out. Then they sewed 1” velcro on the bottom of the hatch carpet pieces. We also had the hatch openings in the carpet cut oversize by 2”. Then we could just rip the carpet over the hatches off when we needed access. The carpet on the hatches stayed put even with our large Lab running around.

Lead sheeting is probably the best, also thick foam if you have the head room.
I can have a normal conservation in my salon, sitting over two Detroit Diesels running at full rated hp. And I have poor hearing.

Lepke said:

Lead sheeting is probably the best, also thick foam if you have the head room.
I can have a normal conservation in my salon, sitting over two Detroit Diesels running at full rated hp. And I have poor hearing.

Click to expand...

that is impressive for sure I have to have elevated speech but not yelling

A "leaky" hatch can contribute 5-10 db, a significant amount and makes gaskets the best bang for the buck you can get in noise control. We have found that cutting our carpet underlayment oversize for hatches that need access provides a kind of "flap" seal that effectively reduces noise from hatches with no or damaged gaskets.

Many boats are going to "loose lay" carpeting with bound edges, which for a boat typically works very well as the carpeting usually can't go anywhere anyway as its constrained by bulkheads and cabinetry.

And Al, be sure your before / after tests are same / same. Taken in the same place under the same conditions. If you took the "before" at cruise RPM no load in the slip, take the "after" the same way.

Nice to hear so many are pleased with our product and service.

Thanks, Steve

FlyWright said:

Right...everything floats and stays stationary. My carpet has floated on a felt pad for 11 years that I've owned it without incident. Makes it easy to pick up to access the hatches.

Maybe Steve can answer the question about noise from the hatch seams without overlap. I suppose every boat is different. My hatches are not tight fitting so the overhang was critical, IMO. Tough to quantify the difference without testing, though.

Click to expand...

Keysdisease said:

We have found that cutting our carpet underlayment oversize for hatches that need access provides a kind of "flap" seal that effectively reduces noise from hatches with no or damaged gaskets.

Click to expand...

Does that not give you a hump around the hatches?

If the hatches are "wrapped" -- i.e., carpet at least, and maybe the underlayment too, are folded over the edges of each edge where the hatches meet the main deck -- does that not provide some sound abatement around the hatches?

Can Soundown be installed that way?

Or when wrapping, do folks usually cut the underlayment flush with the edges and fold the carpet over the top of all that?

(Our hatches were completely covered with fully-tacked carpet, so I cut our carpet open around the hatches myself... which means I've not seen first-hand how it's really supposed to be done...)

-Chris

I often wondered how that heavy rubber sold as shower underlayment would work.

dB sound meter apps are available on cell phones these days, often free.

I got out last week and recorded the new sound levels at the same location and in the same manner as the original measurement before the pad was installed. Here are the before and after screenshots to compare results.

The left graph is before pad installation and the right graph is after the pad was installed. The yellow line represents the peaks during the recording period and the white line is the current level. The white line dropped each time I grabbed the screenshot presumably due to my hand and fingers covering part of the cellphone mic. So let's ignore the white lines and focus on the yellow peak recording.

Each recording was taken at the lower helm along centerline, at ear level (~5.5 ft), at cruise power of 1800 RPM and with all doors, windows and hatches closed. I drew a line through each recording (on paper) to represent the average or mean of the measurements for comparison. I documented those means in the table below to show numerically what is represented graphically in the images.

Summary: The measured noise level improvements on my boat varied with frequency, as expected. The low frequency below 500 Hz was minimally impacted. Above 500 Hz, the dB improvements ranged from the mid teens to low 20s. To me, this represents a value that I cannot quantify in my head but in the boat, it makes a profound difference. I found that I was using lower volume for my news and music listening while enroute, phone conversations were easy without needing to reduce power to hear better and the ambient noise level just seemed muffled and less obtrusive. In terms of noise attenuation, I score this improvement successful and welcome.

The other factor in my carpet underlayment upgrade was comfort under foot as a carpet pad. I chose the 1/2 in foam/1 lb vinyl and find the plush feel very comfortable...even relaxing to my feet. I'm glad I didn't opt for the 1/4 inch foam.

Surprisingly, I really like the carpet underlayment that I installed in the passageway down below. Before this, I had no pad in that section and each step was like a step on a hard surface. Now as I step off the fwd steps to the carpet below, the foam pad softens the step and feels great.

I hope this helps others who are deciding how to attenuate the noise and soften the feel of their vessels. Again, many thanks to Keysdisease Steve for his expertise in this significant upgrade.

Awesome. As we had discussed the choice of 1lb barrier was a compromise for the hatches as the 2lb barrier product is twice as heavy and not nearly as flexible. The 2lb would have impacted the lower frequency noise more, but would have made dealing with the hatches more difficult.

Very happy to hear you are pleased with performance.

To answer Ranger's question, the goal is full coverage and tight sealing. Anything less creates a "leak" for the noise to enter through a loose fit hatch or "flank" any noise insulation to a non insulated section.

FlyWright said:

Summary: The measured noise level improvements on my boat varied with frequency, as expected. The low frequency below 500 Hz was minimally impacted. Above 500 Hz, the dB improvements ranged from the mid teens to low 20s. To me, this represents a value that I cannot quantify in my head but in the boat, it makes a profound difference. I found that I was using lower volume for my news and music listening while enroute, phone conversations were easy without needing to reduce power to hear better and the ambient noise level just seemed muffled and less obtrusive. In terms of noise attenuation, I score this improvement successful and welcome.

The other factor in my carpet underlayment upgrade was comfort under foot as a carpet pad. I chose the 1/2 in foam/1 lb vinyl and find the plush feel very comfortable...even relaxing to my feet. I'm glad I didn't opt for the 1/4 inch foam.

Click to expand...

I used foam window insulation tape like the one linked below for around engine room access doors and on the bottom edges of access hatches. Made a pretty big difference.

https://www.uline.ca/Product/Detail...VlP5kCh2vFQjAEAQYAiABEgJpI_D_BwE&gclsrc=aw.ds

Exactly, any kind of gasket or seal is the best cost / performance dollar you can spend for noise reduction. A very easy and inexpensive way to determine if you would benefit or not from gasket install or replace is to just take some masking tape and seal up the hatch or door. This should give a pretty quick and easy indication if you might benefit from new gaskets

MurrayM said:

I used foam window insulation tape like the one linked below for around engine room access doors and on the bottom edges of access hatches. Made a pretty big difference.

https://www.uline.ca/Product/Detail...VlP5kCh2vFQjAEAQYAiABEgJpI_D_BwE&gclsrc=aw.ds

Click to expand...

Al,

Thanks for the comrehensive and timely follow up.

Best Wishes,

Keysdisease said:

To answer Ranger's question, the goal is full coverage and tight sealing. Anything less creates a "leak" for the noise to enter through a loose fit hatch or "flank" any noise insulation to a non insulated section.

Click to expand...

I get that leaks would be less effective.

I'm just stumped trying to figure out how to get a flat floor with the underlayment overlapping underlayment where the hatch seams meet the main saloon sole.

-Chris

You don't overlap underlayment or carpet, you cut oversized on the hatch a
by a couple of inches and that acts like a flap seal. The underlayment and carpet butt together

ranger42c said:

I get that leaks would be less effective.
I'm just stumped trying to figure out how to get a flat floor with the underlayment overlapping underlayment where the hatch seams meet the main saloon sole.
-Chris

Click to expand...

Steve, Last is Hadik?

ranger42c said:

I get that leaks would be less effective.

I'm just stumped trying to figure out how to get a flat floor with the underlayment overlapping underlayment where the hatch seams meet the main saloon sole.

-Chris

Click to expand...

Chris, If you look at the 4th pic of the original post, you'll see the missing hatches and the "overlap" gap left when the hatches and their pad covers are removed. The cut of the pad never lies directly above a hatch gap...it's 2 inches beyond the limit of the hatch.

Keysdisease said:

You don't overlap underlayment or carpet, you cut oversized on the hatch a by a couple of inches and that acts like a flap seal. The underlayment and carpet butt together

Click to expand...

FlyWright said:

Chris, If you look at the 4th pic of the original post, you'll see the missing hatches and the "overlap" gap left when the hatches and their pad covers are removed. The cut of the pad never lies directly above a hatch gap...it's 2 inches beyond the limit of the hatch.

Click to expand...

Think I'm getting what you're saying. Your 4th pic is with the hatches open, yes?

OK, so in that situation the underlayment covers the hatch seams... but then you also said your carpet is wall-to-wall and floating, so to expose your hatches the whole top carpet has to come up. Yes?

I think I can't do that in our saloon... too much furniture, a pedestal table (pedestal surrounded by carpet), etc.

IOW, I need to be able to lift each hatch -- and it's attached underlayment and carpet -- without lifting the surrounding carpet.

-Chris