Wifi and plaster walls

moglia

Member
SoSH Member
Jul 16, 2005
651
Asheville, NC
I've moved into a new house recently, ~2,000 square feet across two floors. Getting a strong wifi signal to all areas has been surprisingly difficult, and there are also a number of dead zones. I have AT&T fiber and am using their router and range extender on the main floor (opposite ends of the house), and a TP-Link range extender in the basement.

Recently I found info that the metal mesh used in plaster walls contributes to a poor wifi signal, and this seems to be the likely culprit. Has anyone dealt with this issue and come up with a working solution? Powerline adapters wifi adapters look like a possible solution but the implementation reviews I'm seeing are all over the place.
 

nattysez

Member
SoSH Member
Sep 30, 2010
8,411
My experience is that the new Nest WiFi devices -- one router and one mesh node -- create a mesh network that mostly overcomes the same problem in my ~1500 sq ft. house. I don't know if "range extenders" create a mesh network, but I've had much better luck with the Nest devices than I did with a router + range extender.
 

begranter

Couldn't get into a real school
Silver Supporter
SoSH Member
Jul 9, 2007
2,344
I've moved into a new house recently, ~2,000 square feet across two floors. Getting a strong wifi signal to all areas has been surprisingly difficult, and there are also a number of dead zones. I have AT&T fiber and am using their router and range extender on the main floor (opposite ends of the house), and a TP-Link range extender in the basement.

Recently I found info that the metal mesh used in plaster walls contributes to a poor wifi signal, and this seems to be the likely culprit. Has anyone dealt with this issue and come up with a working solution? Powerline adapters wifi adapters look like a possible solution but the implementation reviews I'm seeing are all over the place.
My experience has been that the best thing you can do is hardwire any access points you're setting up rather than having extenders. I've found range extenders are unreliable at best, completely useless at worst. I'm no technical expert but I theorize this is because they have to 1) both capture and then push back out data transmission 2) using the same channel space. If you can also hardwire any higher bandwidth devices (video streaming, gaming etc.) that should help your other devices using the wireless.

Note 2.4 GHZ has a lower total bandwidth, but travels through objects much more effectively than 5 GHZ.
 

Batman Likes The Sox

Not postscient
Gold Supporter
SoSH Member
Dec 28, 2003
2,419
Madison, CT
Had similar issues when I moved into a roughly 3,000 sq ft old house over two floors, was using a slightly older router and range extender.

I've installed the Google Nest router and 3 Google Nest Wifi points, and now have good service in every room, particularly important because we also have poor cellular network coverage here.

I tried it with just the 2 additional points, but couldn't hit everywhere. A bit of trial and error.
 

RG33

Certain Class of Poster
SoSH Member
Nov 28, 2005
7,192
CA
I just installed Spectrum 5G and still had issues with dead spots in my 3000 sq foot house with Google Wifi and the 3 points. I ultimately just got 3 more wifi points, now have 6, and am not having any issues. The walls and shape of my house were causing issues I guess. I've got the most wifi cover per sq foot in America and likely will die of brain cancer, but shit, my SoSH surfing can be done from any nook or cranny in Chateau RG33!
 

moglia

Member
SoSH Member
Jul 16, 2005
651
Asheville, NC
Thanks all for the responses, looks like Nest is the way to go. I'll gladly take the long term brain cancer risk if it means my kids' goddamn devices work while I get my work done.
 

themuddychicken

New Member
Mar 26, 2014
80
I live in an old house, ~2000 sq ft over two floors, with plaster walls. I've dealt with decent wifi (using a Verizon router) for years but trying to stream from a corner room had become a problem. I recently bought a new router and the difference is immense.

I was looking into Nest and various mesh systems, and my friend who has done a much better job of keeping up on tech than I have told me to not bother with mesh for a relatively small house and instead buy an Asus RT-AX88U. It's pricey but he told me it was worth it, and I've been very happy since.

He also advised me that, if I needed to, in lieu of an extender (which he said don't do much to help) you can use your electrical outlets to add an access point. But I never looked into that because the new router fixed the problem so well.
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
Hi. Bumping because I am dealing with exactly this challenge plus I have Frontier (not Fios) bundled for both my internet and cable. I have a really old house with mostly plaster walls. House is about 2,600 sq ft. The internet router is on the bottom floor at one end of the house. It is where it needs to be and there is not a central location. My kids' bedrooms are in the old section of the house, basically as far away from the router as you can be and still be in the house (about 35 feet across and one floor up). My son does quite a bit of gaming and is building his own gaming computer. Beyond that, they need to connect to WiFi for school from their rooms.

My understanding is that it is complicated to replace the standard Frontier router as the cable depends on it. I am open to both the Nest solutions and the Asus one above from @Muddy Chicken.

The constraints are:

1. I still need to be able to connect my Frontier cable box to the router (and I have seen all sorts of warnings of the complexity of replacing that router). We are in a long-term contract with Frontier and I went to war with the only other cable provider (Comcast) so I gotta stick with these guys
2. I am a slow-witted troglodyte

I have a shelf just inside my basement door in the center of the house. It has a pretty direct line up to the kids rooms and would only be separated by a section of floor there. If I went with the Google solution, I was thinking of putting a point there.

Anyway, anyone have experience with making sure the Frontier cable box still works with either the Google nest or the Asus super-router? And, if it can work, can the fix be executed by the aforementioned troglodyte?
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
1) What is the type of your existing internet service? You say not Fios but does that mean Cable or DSL? What maximum advertised speed? (And what speed do you get off a strong-connection device going to something like www.speedtest.net ? What kind of numbers in the weaker part of the house over Wifi?)

2) What is the make and model of the modem+router device you have now from Frontier?

More than likely Frontier is using MoCA outputs from the modem+router to service the cable box. Assuming I am correct, it will be a pain to remove the Frontier-supplied modem+router box completely, even for someone pretty technically skilled it could be something of a project.

You can more than likely use a powerline extender pair directly off of the existing Frontier router+modem box, assuming you have a spare ethernet port on it. You'll want one of the ones that has a Wifi extender integrated given what you described, but ideally your sons gaming computer can hook up to the ethernet port on the far end device. Some more info about powerline networking is here but don't buy more speed than you need (not much point in having in-house speed greater than what you are getting from Frontier, thus question #1 above).

You can also go for the Google/Nest Wifi but you'll be better off putting that into some kind of bridging mode, rather than having stacked/chained routing which can make a mess of some things. (Again, possibly above your troglodyte threshold.)

If your house is really, really old (?) the wiring can affect the quality of the powerline networking - I don't have a lot of experience on how bad that really is, since I've always lived in houses built within the last 30 years. I'm also assuming you keep your basement at least above freezing at all times, since some gear (probably including the Frontier modem+router box doesn't like things that cold).

Assuming you have something like 100-150Mbps service, something like this kit for $48 (prime eligible) would probably do the trick, even with old wiring it might be an upgrade over the issues you are having with plaster + wifi right now. You might also need to buy 2 ethernet cables, unless you have some extras lying around. One needs to reach from the Frontier modem+router to the closest AC outlet. The other needs to reach from the closest AC outlet in your sons' room to his gaming PC.

Note: sometimes the powerline adapters cover both outlets, depending on exactly the style and placement of the AC outlets you have. Some of the "fancier" ones have a pass-through outlet because of this, but they are usually more expensive. In any case, you aren't supposed to connect them via a power strip (but if you get the pass-through, you can plug the power strip into that.)
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
@cgori

Thanks so much for the response

1. My internet is DSL. Theoretically I am supposed to have 200 mbps and they advertise it as 5G. In practice in the downstairs it seems to range from 60-150 mbps. I just ran a speed test and got 88. In the weaker part of the house it seems to range from 40-60. My kids definitely would say it drops below those numbers and I believe them, I just have never seen it myself.

2. The modem/router is Arris model# NVG488Q

34727

The kit you described seems awesome. So I plug the larger end into an open ethernet port on the router and then the other end is plugged in upstairs. My son can run an ethernet cable directly to it and get very fast speeds, and the wifi generally is improved (for non-wired devices). Is that right?

Our electrical system has two different breaker boxes. I realize this might be more of an electrician question, but I wonder if that impacts the ability to piggyback the houses electrical wiring. The good news is, both the plugs that I think I would use are on one breaker box. The house was built in 1868 and has been through a bunch of renovations since then. I am not sure when the electrical wiring was replaced.

Anyway, this seems like a great place to start. Unless something I have said here tells you otherwise, I am happy to go buy this today and thank you very much!

edit: There is actually an answer in the Amazon Q+A that says it works across 2 breaker boxes. So I guess that answers that.

Second edit: Looking for one with the pass-through outlet is tough. I don't think I can give up a whole outlet. I'm happy to pay extra, but seems like they are sold-out all over the place.
 
Last edited:

Couperin47

Member
SoSH Member
How old is the house ? Plaster walls prior to 1947 virtually always meant plaster over wood lathe, which blocks the inherently weaker 5 Ghz band but is penetrated decently by 2.4 Ghz signals. Plaster from 1948 til it was mostly abandoned in favor of gypsum board in the 70's means plaster over metal lathe and that's close to a Faraday cage which means you're basically screwed without multiple access nodes....
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
How old is the house ? Plaster walls prior to 1947 virtually always meant plaster over wood lathe, which blocks the inherently weaker 5 Ghz band but is penetrated decently by 2.4 Ghz signals. Plaster from 1948 til it was mostly abandoned in favor of gypsum board in the 70's means plaster over metal lathe and that's close to a Faraday cage which means you're basically screwed without multiple access nodes....
House is really old. Way before 1947. Our current WiFi is set up so there is a 5g and a non-5G option. So maybe, that is to address the issue you reference.
 

Couperin47

Member
SoSH Member
Then you have wood lathe. 2.4 will penetrate well, 5g will be blocked somewhat and it really gets blocked by any masonry (like the large 3 flu center chimney in my house). Real plaster over wood lathe is more dense than today's wallboard so all signals will be somewhat weaker than modern construction, but not hopeless if metal lathe is back there....
 

Monbo Jumbo

Hates the crockpot
Lifetime Member
SoSH Member
Dec 5, 2003
25,229
the other Athens
I have an AT&T 50mb fiber connection. The wifi has never been great in this house, and recently got considerably worse with my devices frequently disconnecting and reconnecting. Some googling found lots of AT&T customers with this problem. Consensus seemed to be that the wifi radios in the ARRIS BGW210 gateway/router are crap.

I have, thanks to a handy youtube here, added a Netgear Orbi router and set the Arris settings as close to bridge mode as possible per that youtube vid. So far so good, ,the wifi in the house is clearly stronger, and I haven't seen a drop yet.
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
I have an AT&T 50mb fiber connection. The wifi has never been great in this house, and recently got considerably worse with my devices frequently disconnecting and reconnecting. Some googling found lots of AT&T customers with this problem. Consensus seemed to be that the wifi radios in the ARRIS BGW210 gateway/router are crap.

I have, thanks to a handy youtube here, added a Netgear Orbi router and set the Arris settings as close to bridge mode as possible per that youtube vid. So far so good, ,the wifi in the house is clearly stronger, and I haven't seen a drop yet.
Thanks Monbo. I may try that myself down the road.
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
@cgori


1. My internet is DSL. Theoretically I am supposed to have 200 mbps and they advertise it as 5G. In practice in the downstairs it seems to range from 60-150 mbps. I just ran a speed test and got 88. In the weaker part of the house it seems to range from 40-60. My kids definitely would say it drops below those numbers and I believe them, I just have never seen it myself.

2. The modem/router is Arris model# NVG488Q

(snip very blurry :p picture)

The kit you described seems awesome. So I plug the larger end into an open ethernet port on the router and then the other end is plugged in upstairs. My son can run an ethernet cable directly to it and get very fast speeds, and the wifi generally is improved (for non-wired devices). Is that right?

Our electrical system has two different breaker boxes. I realize this might be more of an electrician question, but I wonder if that impacts the ability to piggyback the houses electrical wiring. The good news is, both the plugs that I think I would use are on one breaker box. The house was built in 1868 and has been through a bunch of renovations since then. I am not sure when the electrical wiring was replaced.

Anyway, this seems like a great place to start. Unless something I have said here tells you otherwise, I am happy to go buy this today and thank you very much!

edit: There is actually an answer in the Amazon Q+A that says it works across 2 breaker boxes. So I guess that answers that.

Second edit: Looking for one with the pass-through outlet is tough. I don't think I can give up a whole outlet. I'm happy to pay extra, but seems like they are sold-out all over the place.
You've got the idea of how to use it 100%. One end plugs into open router port via ethernet and the other end (with the wifi repeater) goes upstairs. Run the other ethernet cable to the gaming PC. (I would guess the bigger plug adapter is the one that goes upstairs, but the directions should indicate for sure). There's some kind of pairing process that happens between the two adapters - usually you press a button on one end then on the other end, get your kids to help you :p

You can think of the powerline kits as being like a tunnel going through a mountain. You've got an antenna on one side (your Frontier router) but the mountain (your plaster walls) block the signal from reaching the far side. So you make a tunnel, using the AC power lines, and put up another antenna on the far side of the mountain (the wifi repeater part of the kit) to go around the plaster.

I would also say that putting more than 2 of these powerline things in can cause weird results. It usually works but can be a lot more complicated too, so try to avoid that if you can. I don't see any reason why you will need it at the moment.

Let us know how it goes.

NOTE: I know the kit says 600mbps. I hope it's clear that it can't "manufacture" extra speed beyond what you get from Frontier directly. It's just removing a bottleneck from inside your house.
 
Last edited:

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
You've got the idea of how to use it 100%. One end plugs into open router port and the other end (with the wifi repeater) upstairs. Run the other ethernet cable to the gaming PC. (I would guess the bigger plug adapter is the one that goes upstairs, but the directions should indicate for sure). There's some kind of pairing process that happens - usually you press a button on one end then on the other end, get your kids to help you :p

You can think of the powerline kits as being like a tunnel going over a mountain. You've got an antenna on one side (your Frontier router) but the mountain (your plaster walls) block the signal from reaching the far side. So you make a tunnel, using the AC power lines, and put up another antenna on the far side of the mountain (the wifi repeater part of the kit) to go around the plaster.

I would also say that putting more than 2 of these powerline things in can cause weird results. It usually works but can be a lot more complicated too, so try to avoid that if you can. I don't see any reason why you will need it at the moment.

Let us know how it goes.

NOTE: I know the kit says 600mbps. I hope it's clear that it can't "manufacture" extra speed beyond what you get from Frontier directly. It's just removing a bottleneck from inside your house.
Gotcha. And yep I understand that this isn't going to manufacture speed. If it can just halve the degradation of speed from the living room to the kids' rooms, I am going to be thrilled. Thanks again!
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
They arrived today. On the plus side, it was a very clear system to set up and became functional right away.

To the negative, the signal seems notably worse on the extended network than the (degraded) signal from the original wifi. Going to keep it for a bit and see if we can find a circumstance where it improves things. My guess is that the (potentially very very old) electrical system in the old part of the house doesn't work as well with this system as elsewhere. It was definitely worth a shot though and I appreciate the guidance @cgori
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
They arrived today. On the plus side, it was a very clear system to set up and became functional right away.

To the negative, the signal seems notably worse on the extended network than the (degraded) signal from the original wifi. Going to keep it for a bit and see if we can find a circumstance where it improves things. My guess is that the (potentially very very old) electrical system in the old part of the house doesn't work as well with this system as elsewhere. It was definitely worth a shot though and I appreciate the guidance @cgori
Well, that's a bummer. Is it also worse on the directly (ethernet) connected gaming PC? If so that would rule out the electrical system as a bottleneck. At which point it might be that the setup of the wifi extender needs to be tweaked (bands, frequencies, whatever).

But if the hardwired gaming PC has crappy speeds, then yes, it means that your old electrical system isn't playing well with the powerline communications. (I believe the standard SoSH advice at this point when all else has failed is to get a gun.)
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
Well, that's a bummer. Is it also worse on the directly (ethernet) connected gaming PC? If so that would rule out the electrical system as a bottleneck. At which point it might be that the setup of the wifi extender needs to be tweaked (bands, frequencies, whatever).

But if the hardwired gaming PC has crappy speeds, then yes, it means that your old electrical system isn't playing well with the powerline communications. (I believe the standard SoSH advice at this point when all else has failed is to get a gun.)
It is also worse on the PC. That's why I assumed the problem was the transmission through the electrical system. Right?
 

DrBlinky

Member
SoSH Member
Jun 18, 2002
821
Cranston, RI
It is also worse on the PC. That's why I assumed the problem was the transmission through the electrical system. Right?
I've used the power line adapters in the past (brand was ZyXEL, I believe.) While they did work across breaker boxes, there was a significant difference in speed as compared to using two outlets coming off the same box. The ZyXELs had a color LEDs showing the quality of the transmission. When I was going across boxes, it was typically red, sometimes yellow. On the same breaker box, always green.

You noted earlier that the outlets you'd be using were on the same breaker box, so that may not be the cause of your speed issue, but I'd confirm to be sure. And if they are crossing boxes, I'd recommend testing using two outlets off the same panel.
 

EdRalphRomero

wooderson
SoSH Member
Oct 3, 2007
4,470
deep in the hole
I've used the power line adapters in the past (brand was ZyXEL, I believe.) While they did work across breaker boxes, there was a significant difference in speed as compared to using two outlets coming off the same box. The ZyXELs had a color LEDs showing the quality of the transmission. When I was going across boxes, it was typically red, sometimes yellow. On the same breaker box, always green.

You noted earlier that the outlets you'd be using were on the same breaker box, so that may not be the cause of your speed issue, but I'd confirm to be sure. And if they are crossing boxes, I'd recommend testing using two outlets off the same panel.
That is worth a try. I am going to try some different outlets to get different results. Thanks!
 

tmracht

Member
SoSH Member
Aug 19, 2009
3,070
So based on this thread I jumped on an Eero three pack when it was on sale for prime Day. I have a 2800 ft² house with plaster walls and ceilings in a lot of the rooms I had been using a super high-end nighthawk which got good/great reception in probably 80% of the house and the last 20% were just nightmarish.

Installed the Eero network yesterday, I now have basically 100mbps throughout the house.

Something weird was going on initially and none of my wired devices were getting IP addresses so I had to blow up the network and start over. But since then everything's been working great. Reference my house was built in 1983 in case anyone else stumbled through here and wonders that worked or not.
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
I'm curious, for your setup, what is the backhaul between the Eero devices? Wireless or wired?
 

tmracht

Member
SoSH Member
Aug 19, 2009
3,070
Network setup my charter cable comes in on first floor northwest corner. That's where they put cable modem. So I have a 1ft jumper from cable modem to first eero (hardwire) family room is on south west corner so I have a hard wire from that eero through the basement and up into family room to another eero. That then goes to a gigabit switch to feed all the entertainment in the family room (gaming consoles, smart tvs (yes two one for main screen one for toddler tv)). Then in the center upstairs I have a free standing wifi connected eero.

I made sure to turn on the upstairs last so only devices that would need it would connect. Balance ended up as:

7 devices on gateway.
15 devices on family room.
2 on upstairs eero.

Hope that makes sense.

Edit: typos.
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
Sounds like you have a mix, with gigE backhaul for where most of the devices are (family room). The upstairs eero is wireless-backhaul and seems to work well through the plaster/walls though?
 

jcaz

Member
SoSH Member
Jun 8, 2009
383
Bumping an old thread because I'm a techno-dumb-dumb and need help. We recently converted our third floor attic space into the home office. Mrs. JCaz does CAD production working on big files that are stored in the cloud working from a desktop PC. So, we need a wired connection on the third floor that will reliably handle high bandwidth.

We have Cable internet from Rogers (in Canada) with the modem on the first floor. Sadly, when we did the renos, we didn't run CAT5 so there's no wired connection available.

Here's what I think I understand. There is the possibility to create a wired connection using electrical circuits. I can also get a wifi extending system that may have a port into which the wired connection to the desktop can connect.

I'm looking for best quality and can get the expenses reimbursed, so price (within reason) is not a problem.

I also am a techno-dumb-dumb so I really am looking for plug and play technology, i.e., very little technical oversight from me...

Thanks in advance for suggestions.
 

AlNipper49

Huge Member
Dope
SoSH Member
Apr 3, 2001
44,840
Mtigawi
The power line adapters are only like $50 and if it doesn’t work then you can always return it. I use a few of them in situations like yours and they run perfectly fine.

TP-Link Powerline Ethernet... View: https://www.amazon.com/dp/B084CZMYNM?ref=ppx_pop_mob_ap_share


You can also get a wife mesh system that would probably work as well, but I’d get the power line adapter in addition to. For $50 you’ll be able to keep it even if you also get a Wi-Fi mesh that works.
 

SumnerH

Malt Liquor Picker
Dope
SoSH Member
Jul 18, 2005
31,842
Alexandria, VA
Yeah, definitely try the powerline adapters. In my experience, they either work wonderfully or not at all, but they're cheap and if they work they're great and simple.
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
This slightly newer one View: https://www.amazon.com/dp/B01H74VKZU/
is supposedly better (roughly 2x faster). They also have the outlet passthrough which can be very handy in some cases where you don't have a lot of free receptacles. They are $90 for the pair (instead of $50, I think).

I had used much-older powerline adapters in my previous house for years, they worked great.
 

jcaz

Member
SoSH Member
Jun 8, 2009
383
The TP-Link AV2000 has been ordered - with delivery today - from Amazon. I'll report back on performance.

Thanks a lot. SOSH is, as the kids used to say, the bomb.
 

cgori

Member
SoSH Member
Oct 2, 2004
3,994
SF, CA
The TP-Link AV2000 has been ordered - with delivery today - from Amazon. I'll report back on performance.

Thanks a lot. SOSH is, as the kids used to say, the bomb.
Just a reminder, you might need some extra 6'/2m cat6 cables to connect things together, if you don't have a bunch handy already.
 

jcaz

Member
SoSH Member
Jun 8, 2009
383
So, finally got around to setting this up. Setup was ridiculously easy.

Instructions say that the two adapters have to be plugged in on the same circuit. I tried that first and got great performance 200+Mbps downloads and 30 Mbps upload speeds.

I then moved the adapter to where we need it, not on the same circuit. The performance changed to ~30Mbps download but still ~30Mbps uploads. Does that seem right? Aren't downloads normally >> than uploads? Any thoughts?
 

Max Power

thai good. you like shirt?
SoSH Member
Jul 20, 2005
7,838
Boston, MA
So, finally got around to setting this up. Setup was ridiculously easy.

Instructions say that the two adapters have to be plugged in on the same circuit. I tried that first and got great performance 200+Mbps downloads and 30 Mbps upload speeds.

I then moved the adapter to where we need it, not on the same circuit. The performance changed to ~30Mbps download but still ~30Mbps uploads. Does that seem right? Aren't downloads normally >> than uploads? Any thoughts?
No, the device inside your home has equivalent send and receive speeds. Your connection to the cable company has greater download than upload. So you're limited to the smallest number at each link of the chain. The smallest number for uploads is still 30Mbps because each link can handle that.
 

jcaz

Member
SoSH Member
Jun 8, 2009
383
No, the device inside your home has equivalent send and receive speeds. Your connection to the cable company has greater download than upload. So you're limited to the smallest number at each link of the chain. The smallest number for uploads is still 30Mbps because each link can handle that.
Got it. Thanks. So, if I were to put both adapters on the same circuit, I wouldn't see an improvement?

And when I do the speed tests, it reports 30Mbps as "fast, able to handle multiple devices streaming HD or ..." 30Mbps is good, yes?
 

Max Power

thai good. you like shirt?
SoSH Member
Jul 20, 2005
7,838
Boston, MA
Got it. Thanks. So, if I were to put both adapters on the same circuit, I wouldn't see an improvement?

And when I do the speed tests, it reports 30Mbps as "fast, able to handle multiple devices streaming HD or ..." 30Mbps is good, yes?
You'd see an improvement in download speeds from the internet. You'd also see an improvement in copying things from one computer to another if that's something you ever do in the house.

30Mbps isn't great, but it may be acceptable. You said there were giant CAD files coming from the cloud to that computer. File sizes are measured in bytes and bandwidth in bits. So multiply the file size by 8 and divide by the bandwidth to see how long it would take to download the file. Let's say you have a 50MB file. That's 50 x 8 = 400Mb/30Mb/s = 13 1/3 seconds. If your bandwidth were 200Mbps, you're looking at 2 seconds to open the same file. When you're saving it, you're limited to 30Mbps upload no matter what, so that's 13 seconds. But that usually happens in the background.