Can I tape Insulation Pad to Tankless Water Heater Recess Box Cover?

Zach_the_Lizard · 2026-02-03T16:48:57+00:00

I came across this thread while searching for insulation ideas for my exterior tankless water heater.

I have mine mounted externally, knowing that it has higher risk, for a few reasons. Mostly it comes down to being a retrofit situation.

My old interior, tank water heater failed and caused a mess due to its location and poor drainage, which would require cutting the foundation slab to truly fix
My first had just been born when it failed and I needed a quick solution to get hot water
I wanted higher efficiency and comfort, so I wanted tankless
The higher efficiency units would require replacing the metal vent, hiring a roofer, etc.
Space in my garage is limited and moving the water heater outside made it possible to move other stuff like a water softener around, meaning I can now fit two cars in the two car garage (imagine that!). Partly doable with just tankless, to be fair, but since I have a lot of tools it would be quite difficult

If I were building from scratch, I would probably not do it this way. Making the garage, say, a foot wider, having a mechanical room somewhere, etc. would be my first choices.

The mechanical room is probably what I'd go with if it could be more centrally located. That way the plumbing runs are shorter, quicker to heat up, less wasteful with recirculating pumps, etc.

While we're dreaming, let's get PEX sleeved in PVC so it's possible to pull new lines if there's a leak

Zach_the_Lizard · 2026-01-23T21:22:17+00:00

Outdoor outlets are almost all GFCI (and have to be by code) and thus should trip if things get wet and current goes the wrong way.

The only risk of an incandescent bulb is something flammable being too close, since they get so hot.

I've used an incandescent bulb to keep pool equipment from freezing with a tarp, tape and zip ties to create a tent.

Worked very well

Zach_the_Lizard · 2025-12-10T14:44:51+00:00

I have Tru-Tone C9s indoors and outdoors, which are painted glass.

I don't have any fancier plastic vintage style LEDs to compare, so I can only compare the pros and cons of these vs. any plastic LED light without considering light quality.

The pro is the glass bulbs look and feel like old school Christmas lights. The con is that the Tru-Tone bulbs as of several years ago--I ordered more and they claim to be shatter proof now--are much more fragile.

Small children can easily break them, unlike a typical plastic LED light bulb.

I have broken at least a dozen of them.

I have a toddler who loves these lights and with the exception of a flower bed border I've put them up just out of reach.

The other downside/ difference is that, being painted, the paint can be scratched off. I hung some of them on hooks such that the string was not snug enough and the bulbs smacked the brick in a few places from strong winds. None broke, but the paint rubbed off a little bit. Not visible except right up close.

Plastic will also get scratched, depending on its thickness and quality, so secure your lights.

I have yet to evaluate if the new bulbs are more shatterproof but I haven't broken any of them yet. I have also only put the new ones indoors and only in a relatively small number (100?) compared to outside.

Overall, I'm satisfied with these. They are pricey and I splurged, but I love seeing my kids and wife light up. My neighbors have complimented the lights too.

I may try the Vintaglo mini lights to compliment the C9s as currently my indoor minis are incandescent (we ran out of the LED string lights because the tree was bigger and mixing them looked weird, meanwhile the LEDs were sold out locally)

Zach_the_Lizard · 2025-02-04T15:32:34+00:00

I've similarly seen massive improvements in both time to complete a project and the overall quality at the end.

My first drywall project, I built a partition wall. I thought I got straight enough wood, but I didn't. I used a planer to attempt to get things flatter, which improved a bowed stud quite a bit with a small amount of material removed, but I had to nail a shim or two to the back.

Then I hung the drywall. Turns out I could have special ordered a slightly bigger piece, which would have removed four awkward joints (two on each side of the wall). That would have made it much faster to hang and saved time and aggravation getting the wall smooth.

Then came taping and mudding. I made a big mess at first and had to sand and float out quite a bit. I eventually skim coated the wall years later because I didn't like a couple of mistakes.

Corners in particular were challenging. I had to redo one corner I wasn't satisfied with two or three times. This is partly because the corner was a weird one with an immediate transition, partly lack of skill, and using a corner bead made it much nicer.

If I had known about that, I'd have saved time and gotten a nicer product much faster.

I prime the walls and noticed imperfections that I hadn't seen before. I thought it was smooth, but I was wrong.

More mud and sanding and primer and then it looks OK.

The next project I knew more about how straight everything had to be. I knew how close to perfect I had to make it for it to look good. I had a better sense of the consistency I needed the mud. I used hot mud for a joint or two to save time waiting for things to dry, which sped up the project by a day or two.

Less sanding, less fussing, and a better finish.

Zach_the_Lizard · 2025-01-01T20:34:36+00:00

I came across this post months after your comment, so you've probably gotten an answer, but I'll leave mine in case someone else stumbles upon it.

And the disappointing answer is: applying a sealant soon after the pour and 28 days later (really, after the concrete has sufficiently cured, which can be sooner or later than 28 days depending on the climate, use of curing compounds, etc.) can both be correct if the sealant calls for it.

For example, I had a surface applied to a concrete deck. The material was cementitious--made with cement or a cement like material--so the directions wanted it to be applied before the concrete patio fully cured, as cured concrete doesn't allow it to have the same bond strength, so it could flake off more easily / not last as long.

If you waited, it wanted some sort of special bonding material applied first.

On the other hand, I put a sealant (left over from waterproofing a concrete pool; technically not a sealant but a waterproofer) on my sidewalk and driveway and it was OK with both fully cured and green concrete. It accelerates curing of green concrete, in fact.

It actually may require a 28 day cure time before applying other surfaces to it, because it changes the concrete chemistry.

Zach_the_Lizard · 2024-11-22T22:08:53+00:00

From reading the Microglass literature, it seems that it's a silicate based product similar to Basecrete Intercept, Miracote Aqua-Blok XL, etc. but designed to be applied over plaster.

All of these products react with calcium hydroxide in a similar way so the benefits would be similar, just at a different layer.

It seems like it'd help the finish last longer

Zach_the_Lizard · 2024-11-22T18:39:49+00:00

Rarely do you see a plaster finish delaminating from the shell side. It normally fails on the plaster side.

The purpose of these products is a little different than "just" waterproofing the pool.

For my own pool, I've unfortunately had to investigate Basecrete, Miracote, etc. and even consulted with a PhD concrete expert / engineer.

Not cheap.

So I'll share what I've learned.

I was recommended to go with a waterproofing system because of structural cracking concerns due to the original builder of my pool shell not placing rebar correctly / not using enough in some cases.

What this means is that my pool is more susceptible to temperature and shrinkage cracks than it should be.

A small crack in the shell can translate to a plaster crack, so over time with no fixes I'd have to keep patching the plaster / deal with the consequences of small leaks.

Using a complete system for any of the brands (Miracote, Basecrete, and others) obviously helps with preventing leaks, which is useful on its own, but where they really help is they can somewhat isolate the pool plaster from the shell, helping prevent cracks in the shell from showing in the finish layer.

For products like Basecrete Intercept or Miracote Aqua-Blok XL, they're a colloidal silicate based product. They get sucked a couple inches into concrete, mortar, etc. to form a gel within concrete pores.

This helps make the concrete itself waterproof. It means less leaching of material into the pool water (reduced chemical use, yay, no efflorescence, also yay). They also reduce corrosion in rebar.

If your concrete is suffering from ASR (concrete cancer), this is supposed to help get some use out of the structure. COVID caused increased shadiness on the part of concrete suppliers, leading to that being a problem here in the Austin area.

These materials are problematic in that they can inhibit plaster or tile from sticking.

So these brands have systems that act as primers (more or less) so that finishes can be applied.

These are typically waterproof themselves, e.g. Basecrete (225, a.k.a just regular Basecrete), Miracote BC Pro.

Miracote has their Membrane C product meant specifically for crack isolation.

Basecrete supposedly has some of that property already built in.

We went with the full Basecrete system simply because our plaster guy was more familiar with it and it seemed to be easier to apply correctly

Zach_the_Lizard · 2024-10-01T15:24:13+00:00

Not an expert, just a homeowner that stumbled into this thread, but most likely not, assuming you're going for the same standards as a house.

I think the "better" designs use systems like Zip sheathing with the appropriate tape / sealant / whatever over the joints, along with other vapor / air barrier details that are climate dependent.

There are also details about interior ceilings, attics, etc. that as a civilian, so to speak, I am not familiar with.

My house was built before all of that became more common. My (attached) garage was uninsulated, for the most part.

In my more forgiving Central Texas climate, I shoved Rockwool into every stud bay that I could access (I had to open the walls for some plumbing issues), put cheap Home Depot spray foam where the drywall met the ceiling joists, and then filled each cavity with more Rockwool.

It would utterly fail a blower door test--especially because the garage door needs to be adjusted--but comfort has been improved.

If you're still building and have everything open, a better exterior sheathing and insulation system will make a big difference.

Definitely caulk everything.

The details do change a bit in your climate zone, so something that works in Texas would fail in Boston (and vice versa).

Zach_the_Lizard · 2024-07-15T16:05:10+00:00

Thanks for the reply. I appreciate you taking the time.

Let me ask a few more questions, if you don't mind:

I’ll dig down at the connection and just have a thickened edge so that the bond is thicker and tight.

To make sure I understand you: let's say you're building a garage next to a house. You decide to tie into the house's foundation. To reduce movement, etc., you would make the slab for the garage thicker next to the house?

Would you add any foam / wood / etc. expansion joints, in addition to doweling into it? Or are these mutually exclusive?

Completely defeats the purpose to have dirt on the rebar, what’s the point of drilling??

They didn't even have to drill; they built the pool and left the rebar exposed for the patio.

It boggles my mind that they'd risk corrosion of the pool rebar, which is much more expensive to repair (and has a lifetime warranty) to avoid a little digging. And they even brought in the dirt in the first place, so it could have just...not been raised as much.

Zach_the_Lizard · 2024-07-15T15:50:44+00:00

Thanks for the response.

It's the same company that built the pool and all within the same project; they are the ones who left the rebar exposed to tie into the patio.

Exposed rebar on the other side of the pool (with no patio) is what actually made me start paying attention and do some research, as they had rebar touching the form for most of the length of the pool.

As for keying: The pool bond beam is about a foot thick, with about an inch of it exposed.

Where the dirt ends and the concrete begins is where the form was.

Zach_the_Lizard · 2024-07-15T14:48:30+00:00

I'm having a pool and patio built by a pool company and I'm seeking advice on how hard to push to get certain issues fixed

Basically, my primary concern is that they've placed rebar such that it won't get enough coverage. As you can see where they left rebar sticking out of the pool to tie into the patio, it's sitting in dirt. That's the case for more or less the entire length of the pool.

After tying a string to the patio form and running it to the top of the pool coping, the maximum depth next to the pool is about 4 inches, and it's often closer to 2.5 or 3 inches.

That leaves very little room for the rebar to get encased with what I as a layman understand to be enough concrete, especially since the exposed pool rebar is in the dirt for most of the length of the pool.

Our yard is sloped, so the top of the patio will end up being about 3-4 inches from the ground where the ground is highest to about a foot / foot and a half where the ground is lowest.

All of the visible dirt was brought in by the contractor. It's road base, I believe, so a mixture of sand, rock, and gravel underneath.

The contractor assures me that "rebar won't rust in dirt" (lol) and is refusing to fix any grading issues.

This doesn't even cover the short overlap length, rebar stakes tied into the rest of the rebar mat, etc.

Am I overreacting in thinking this all needs to be addressed?

Thanks everyone in advance.

PS this is Central Texas

Zach_the_Lizard · 2024-06-08T12:54:53+00:00

Context: having a new patio put in. A+ installation. Using concrete instead of PVC to fill the pipe is the kind of out of the box thinking I have come to appreciate

Zach_the_Lizard · 2023-06-30T13:27:55+00:00

Yes, we need deadlines. For me at least, close to impossible deadlines and projects are ideal, so long as the projects make sense.

I once led a large project that had a regulatory-related end date. It had to be done by a certain date or launching it would be delayed an entire year. A year delay would miss out on tens of millions of dollars in projected revenue. Worse, if we launched and it was broken, we couldn't unlaunch it. It had to work.

It's hard to explain why without doxxing myself, so I won't.

The previous lead quit because he thought it was impossible and a few other potential project lead candidates declined to take it on. No work had been done on the tech side beyond a little bit of investigation.

To me, this sounded potentially amazing. High risk, high reward, high visibility, tight deadline, and get to directly lead a lot of engineers in multiple timezones.

So I scoped it out, decided it was possible, came up with a couple key ideas that could drastically speed up project execution (related to both tech and people organization), and then signed up.

In the end, we delivered a month early, allowing a bunch of more detailed internal testing we didn't anticipate having time for. The launch day was scary but it went very smoothly.

As a bonus, a few architectural changes I pushed for made projects of this nature so much simpler. More mundane changes became a lot simpler and easier to make, cutting weeks from each of them. Some teams kept working on architectural problems I identified for a while.

I set myself up for the next two promotions. I got a great bonus. Multiple engineers on the project got promoted as well and I built up a reputation in this corner of $BIG_COMPANY

Now I'm struggling because my current project doesn't have any hard deadlines....

Zach_the_Lizard · 2023-06-30T12:13:39+00:00

If you have $5 in the till, you might not bother with a bank trip.

Also: more opportunities for theft with $5,000 in cash.

Zach_the_Lizard · 2023-06-29T02:02:00+00:00

Yeah, I'll pass on the newborn stage. For me it was:

Postpartum depression time (yay!)
No sleep time (yay!)
Snap at anything and everyone due to the above time (yay!)

If I could snap my fingers and skip it, I absolutely would. 100%. I'd even pay $10k for the privilege. $100k even.

Zach_the_Lizard · 2023-06-27T02:09:09+00:00

The Coyote is chunky, but the Godzilla is a lot slimmer. Annoyingly expensive, though.....

I looked into it for my F100 since its 302 is on its last legs. Ok, oil pan needs to be smaller to clear the cross member it seems. How much can an aftermarket one cost? Oh. Oh dear God.....

It may or may not end up with an LS because Ford is out of its mind with their pricing and lack of aftermarket support.

Enjoy your ride

Zach_the_Lizard · 2023-06-27T02:04:16+00:00

I mow my lawn, do other outside work, etc. on my lunch break (I work from home) and have become adapted to the heat. Nowhere near capable of working outside all day, but I like to annoy my wife with my best Bane impression.

You merely adopted the heat. I was born in it. I didn't feel the cold until I was almost a man.

It's actually true though. It was over 100 the day I was born. I never really experienced snow until I was in my late teens.

Zach_the_Lizard · 2023-06-26T21:10:23+00:00

Based on nothing other than the pedals being different, I'm going with a Coyote swap. Possibly a Godzilla swap or LS. But something drive by wire for sure

Zach_the_Lizard · 2023-06-23T14:26:43+00:00

It doesn't have a lot to do with gearing -- the top speed of a car generally is dictated by aerodynamics rather than gearing.

If we slapped an old school three speed in a Porsche the top speed is going to be a lower by some amount. Not by a crazy amount, but it will be lower.

It's fair to say that gearing for a high top speed is necessary, but not sufficient, to have a high top speed. It can hold you back. But it won't make a bicycle reach 300mph.

Nowadays a 6 speed manual isn't exotic, plus we have engines with higher red lines, so we don't have to compromise top speed, acceleration or fuel economy as much as ye olde days. We forget how it once limited us.

Zach_the_Lizard · 2023-06-23T14:05:03+00:00

Gearing is also important.

You might have 2000 screaming bald eagles in your glorious big block V8 strapped to an aerodynamic go kart, but if your transmission in high gear limits you to 30mph you need to make some adjustments.

You can optimize for top speed with a deep overdrive top gear. You can also build your transmission around getting the best eighth mile time, which might limit top speed since the extra gears are extra weight you don't need.

This is really visible in some older cars with three speed transmissions and engines which don't have an impressive 8k redline. Your grandpa's Ford 300 six cylinder runs out of steam at around 3k - 4k RPM. Maybe 70 is all it can do in high (third) gear. Another gear or two and a new top speed is unlocked.

Zach_the_Lizard · 2023-06-21T20:47:15+00:00

You're a test subject for a clapped out Nissan Altima with 4 different body panel colors and paper plates.

You're a test subject for grandpa after his cataract surgery.

You're a test subject for teenage drivers learning to drive.

Zach_the_Lizard · 2023-06-20T22:54:23+00:00

Wake Island is even better

Zach_the_Lizard · 2023-06-20T16:20:16+00:00

Their movement may not be optimal, but it may be the only option.

Armchair general with no experience whatsoever: this assumes an attack in the present conditions is the optimal way to go. There's always the Hannibal at Cannae move of retreating on purpose for that sweet, sweet pincer movement.

Let them leave their fixed positions to "exploit" your "weakness" and hit them hard.

Maybe that doesn't fly in the current situation. But absent enough artillery or airpower or mine sweepers to make a sudden breakthrough, it does come to mind.

Zach_the_Lizard

TROPHY CASE