How drilling a hole through my concrete foundation for a mini split system became a 10 hour journey.
Part 11— Designing and building a DIY home recording studio.
The whole story — part 1, part 2, part 3, part 4, part 5, part 6, part 7, part 8, part 9, part 10, part 11, part 12, part 13, part 14, part 15, part 16, part 17, part 18, part 19, part 20, part 21
Why am I even drilling a hole through my foundation?
It’s to help keep my room as sound proof as possible. I’m not going to tie my studio into my home’s existing central air system so, instead, I’ve decided to go a different route and use an independent, standalone ductless system. That way I’m not cutting a big hole into my ceiling for an air vent. Also, using a separate system means I won’t have any direct open air pathways leaking sound in from the other rooms in the house directly into the studio. That also means I won’t be pumping my sound out to everyone else in the house either. Win/win.
If you want to learn a little about the standalone system I chose — which is why I’m drilling the hole — keep reading. If you want to skip instead to where I talk about the specifics of drilling through the concrete foundation, just scroll down a little bit.
Choosing A Mini Split System For The Studio
My research for an independent heating/cooling system — quiet enough to be in the studio with me — led me to a mini split. You can check out what a mini split is here. As I’ll explain, it won’t be as expensive for me to set up as the info in that link eludes to. I realize I’ve seen mini splits in studios before but just never knew what they were.
A mini split has two parts; an air handling unit mounted on the wall in the studio, that runs to the compressor/condenser unit that sits outside. It looks like a mini-me version of what my home already uses. Between the two units there is a “line set” which includes a condensation drain hose, a couple pressurized copper pipe refrigerant supply lines and electrical wiring. The outside unit sits on the ground on a pad which can be made out of various things like cement, foam or rubber, or it can even be mounted to the side of a home/building.
Selecting the best brand mini split for my situation
Advertising led me initially to Mitsubishi which is a great unit, but quite expensive. Quickly wanting to look for some alternatives, I am very grateful to my insanely intelligent friend Jacob Fenn for suggesting I first check out Pioneer’s WYS mini split systems before making a final decision.
Other than Mitsubishi’s great reputation in the mini split arena, I couldn’t see any functional/logical reason to spend almost 3 times as much for what looks like essentially the same capability in the Pioneer. I figure, with the overall 5-star rating Pioneer also has for their systems — along with my friend’s recommendation, it was safe enough to move forward. AND, should something go wrong, I could replace the entire system almost 3 times for the money I would have spent on 1 Mitsubishi system. I think I’m going to be just fine.
As I looked online, I stumbled onto a few other brands that people have also had good experiences with. Most of them are on Amazon which makes them fairly easy to compare with each other to a point. I’m sure there are other ways to compare, but Amazon seemed the easiest for what I was doing. I didn’t find anything that seemed to be offer more or perform better for the price than the Pioneer so I decided to move forward with the Pioneer. Here is a little more info on the one I’m buying if you’re interested. By the way, just so you know, I’m not in any way affiliated with any manufacturer or brand. This is all just FYI to try to pay forward what I have received, by way of info, in abundance from others.
Interestingly, though, as I was looking for the smartest deal, when I was ready to buy, I actually purchased wholesale directly from the manufacturer instead of Amazon. At the time of this writing, the Pioneer WYS12000 230V is $928 on Amazon. Buying directly from the Pioneer mini split store, it was $683 with no tax and free shipping. So, for me it was a no brainer. Done and done! I must quickly add here though that after learning about mini splits, I had called a local HVAC guy to come and look at my room and give me a quote on a system and install. For the same system I bought for $683, he quoted a minimum of $3600. Wait, WHAT?! He said it actually could possibly be as much as $500 more depending on how long it took to install.
I was very forthright with him and told him what I had seen on Amazon. I have no interest in playing the lowest-bid ware game, but I just want to keep my life as low stress as possible and keep things moving along, even if it means paying a little bit more to buy local and have it installed. He said they actually make no money on the systems and are simply charging cost and then all the rest is their profit. He said often the same system can cost as much as $6000 by the time they have drilled the hole in the wall and performed all the other required install labor. He was pushing a different brand all together though because he said dealers only have access to specific brands — and that’s the brand they will push. If I had been sitting on a chair when he gave me that info, I would have fallen off of it for sure! I asked how much he would charge to install one I provide. He said they won’t install a system purchased elsewhere because then they can’t warranty the unit/install. Hmmmmmw, this is going to be interesting. With hundreds and hundreds of people buying these and having them installed or installing them on their own, I decided to proceed with my online purchase. Apparently, these systems arrive pre-charged and ready to go once the lines are all connected, so I may be able to tackle this on my own like so many others have. We’ll see.
I have been buying items online a lot more over the past few years and am comfortable with that now, but I was still a little hesitant to purchase directly from the Pioneer mini split store because I’d be walking away from the Amazon guarantees, so, I asked Pioneer why Amazon was so much more expensive and what I would be missing by buying direct. I also asked if they were undercutting Amazon. They calmly stated they definitely were not undercutting Amazon, and that the difference in cost is simply the increased amount Amazon has chosen to make on that item.
I have no issue with Amazon making money, but this was a big enough difference I chose to buy directly from the Pioneer store. Glad I did. Especially if I end up having to hire someone to help with the install if I find out I can’t do it on my own for some reason.
A couple week later a big semi truck showed up at my home and lowered it down to my driveway and rolled it into my garage.
Temperature Ranges
As a quick important side note, the only reason I would still want to use my home’s heating/cooling instead of a mini split system is if for some reason I had to rely (as my only option), on cooling my studio when the outside temperatures are more or less than 32~122 degrees F (0~50 C), or heating when outside temperatures are beyond the range of 5~86 degrees F (-15~30 C). Because of how mini splits works, they just don’t operate outside of tose ranges. Maybe you live in an area like Antarctica and a mini split just can’t perform the way you need it to, so definitely do your research before buying. I was surprised when I spoke to the HVAC guy to learn that mini split systems are becoming QUITE common now. He said that expensive million dollar+ homes are moving away from central air systems and are going with mini splits in every room now instead. Some mini splits can be purchased for multi rooms where one compressor/condenser can supply 6 rooms or more. Those are $10,000-$15,000 fully installed systems, but give you total per-room temperature control. I think I’ll stick with central air for now and a little single room mini split for the studio.
Mini Split BTU Size — 9,000 vs 12,000 btu
The manufacturers supply a chart that shows which system to buy based on your square footage. I purchased a 12,000 btu system so I would have ample capacity to heat/cool the size of my room which is just under 300 square feet. (I also paid just a little more for the 230V vs 115V for electrical efficiency). I could have probably been fine with the 9,000 btu, but I’d rather spend just a slight bit more so I can have a system working on low fan speed (LOW NOISE/lower power usage), and doing a great job, than using a smaller system having to run the fan on high. As far as noise of the system goes, the fan on high speed produces 40.5dBA and on low only 25dBA. Not bad!
Operating Costs
Although I likely won’t be needing to use it even this much, AHRI Estimated Annual Operating Costs:
- Cooling: $86.00
- Heating: $265.00
Where To Drill The Hole
The installation manual specifies a 2.5" hole be drilled to the outside for this size unit. This gives the supply lines enough room to exit through the wall. Because the copper supply lines are pressurized, they can be installed any direction up/down/sideways, as they find their way to the outside unit. The condensation drain however MUST be sloping down at least 1/4" per foot on its way out of the wall so the condensation can freely drain outside.
This is super easy to accommodate if the mini split is being installed on a floor above ground, because, other than making sure the the hole exiting the house allows the drain to maintain a proper slope as it exits the house , from there, the drain just continues running down towards the ground. It’s also easy to install if it’s being used in a home because you’re likely only drilling through drywall, a couple layers of OSB exterior wall material and some type of exterior stucco or siding — all of which are relatively easy to drill through.
Condensation Drain Requirements
Looking over the install requirements I realized it’s a bit tricker if it’s going in a basement. Here’s why…. the wall unit is still supposed to be installed so the bottom of the unit is around 80" (or higher) above the floor and about 4"-6" (or more) down from the ceiling. In my basement, this recommendation places the drain pipe (exiting the back of the wall unit), about 18" down from the ceiling (including the hat channel/double 5/8" drywall with green glue system I’m using). Running the copper supply lines to the condenser outside isn’t an issue for me because again, they are pressurized, so I can easily run them anywhere I need to on their way out of the wall. I may even be able to run them through the nearby hole that my home’s AC line set runs through if needed. But the condensation drain is the issue. It has to exit maintaining the proper downward slope which because I’m in a basement, means the line will have to remain quite short.
This suddenly made me a little (A LOT)worried that the drain would possibly end up having to be below ground level by the time it exited the wall. This would have required that I make some sort of french drain for it to drain into outside.
The ground level is roughly 19" lower than the inside of my finished basement ceiling — that’s already accounting for the clip/hat channel (1–1/8" see picture below) and the 1–1/4" double 5/8" drywall with green glue in between. Below is an image of the system I will be using on my ceiling.
After measuring, I was very relived to discover the drain would basically be exiting almost an inch above ground level. If I need to, I have some gravel that I can pull back and just scrape the dirt down a couple inches. Shouldn’t be a problem to do that and it will actually make the ground level on that side of the window well more even with the ground on the other side of the window well which is a few inches lower anyway which works out perfectly.
Once I lower the ground level just a little I know I’ll be fine during warm weather when the ground outside is dry, but during winter/spring, the drain could easily end up being covered with snow and eventually melting snow and I don’t want to risk having melting snow pool up and cause water to potentially run backwards and fill the drain hose with standing water. So, what’s cool, is the drain is only about 3' from the edge of my window well so I may be able to just continue running the drain over to the window well which would then give the drain at that point several feet of free fall to the ground. There will be very little condensation coming from the drain though, so I’m not worried at all about it putting any more water in the window well then what already occurs from rain storms and yard sprinkler over spray.
**ON TO THE DRILLING!**
Anyway, with local options being quite thin and requiring a lot of driving around to figure out what I need, I looked online for a good concrete core bit and found this one on Amazon. Based solely on reviews I went for it. What a weird world we live in now to be buying stuff like air conditioning systems and concrete drill bits online.
So, after weeks and weeks of waiting, I finally was able to use the bit. I will quickly jump to the end of the story and say that I really like this bit and would buy it again in an instant. The carbide teeth definitely did their job and other than losing a few of them (more on the reason for that later), the only complaint I have is the the lock screw holding the pilot bit in place kept needing to be tightened from time to time. Other than that, it was a champion and really did a great job!
OH NO!!!
So, moving right along, I realize I will likely be through the wall in about 30 minutes. Until suddenly everything came to a screeching halt. You may notice in the last picture, I started drilling the hole slightly lower than the CENTER mark I had made. I did this just to give my self a little more room to work with as far as placement when hanging the inside wall unit. Before making this decision I had taken a few minutes to review code online to determine where reinforcement rebar would be hidden in the concrete. Based on what I read, I had at least 5 or more inches to play with without any worry of running into rebar.
Well, all I can say is, my decision to move the hole down 1/2" added 8 hours of excruciating effort to my project. Suddenly my drill just wouldn’t go in any further and I looked inside the hole and to my horror saw this:
For some reason, the builder decided to put extra rebar in the wrong place. What made me sick is suddenly realizing that if I would have kept to my original marking of where to drill, I would have literally skimmed over the top of the rebar and no had to think twice about it. Instead, this started the beginning of another entire days work to try to get through it.
Determining My Options
In high school I worked in construction a little bit and at one point spent hours upon hours cutting rebar with an acetylene cutting torch cutting pieces being used to reinforce the new concrete foundation for a big warehouse. Thinking I may be able to get my hands on one I started contacting my neighbors. No luck yet, but I did get a few suggestions including,
Option #1 Drilling another hole in a different place. After measuring I found out that this hole location is actually my only option if I want to have a mini split in my room and a condensation drain that works properly without using some type of additional pump system.
Option #2 Filling the hole back up with quick set cement and then redrilling the hole — using my original center marking instead. This was definitely a smart and viable option, but even though I said earlier that the hole was pretty easy to drill, this is in hindsight after doing what you’ll discover I had to do. At the moment though, the thought of having to redrill those 4.5 inches seemed harder than moving forward through the rebar. Again, I kept holding onto the thought of using a cutting torch somehow.
I immediately looked online to see if the carbide bit I was using would possibly, somehow have the composition and strength to drill through the extremely hard rebar. All I found were very mixed reviews and opinions. I decided to just go for it come-what-may. After about 30 min of pushing and pushing and pushing, what you see in the last picture is all I could get that meaty hammer drill to do. I lost a few teeth on the bit in the process and feeling very defeated, decided to stop. I realized that once I did somehow make it through the rebar, I would still need this hole saw to finish drilling the second half of the hole, which wouldn’t be possible if I kept knocking off the remaining carbide teeth.
Side note:
I did learn that If I was using a spinning drill rather than the hammer drill, the carbide would in fact have been able to make it the rest of the way through the rebar. My problem however is the bit has a BullDog type connector at the end and the industrial spinning drill I am using is only compatible with standard bits. So, rather than a smooth spinning motion, the hammer action was causing the carbide teeth to break off. Without any option to find a bulldog compatible drill that night, I had to stop and regroup.
Attempt #2 — Buying A Metal Hole Saw
So, realizing at 10:30pm my hole drilling was at a sudden end for the night, I closed up shop and tried to calm my frustration. Still wanting to try to cut through the rebar, and without any access to a cutting torch yet, I decided to go to Home Depot early the next morning and buy the meanest looking metal hole saw I could find. I found one for $22 (which was a little painful considering the concrete bit would have been all I needed if I hadn’t moved my mark), but I was starting to feel a little encouraged that this was going to have more cutting power than the concrete bit and would get me back on schedule. Plus, it has a standard drill end on it so I can use it with the industrial spinning drill I’m using. AND, it is called DIABLO so it better live up to it’s name and work!
Well….
After 30 min of brute strength standing on a ladder pushing and trying to get the metal cutting saw to eat through the rebar I stopped. I realized a couple things. First of all the pilot bit in the metal hole saw had to come out, because it was pushing against the concrete and not letting the bit cut in any further. I took a few minutes with the cold chisel and sledge knocking cement out up above the rebar so the metal saw wouldn’t get dull grinding into cement. With the cement removed a little and the pilot bit gone, I was able to make some more progress. But after another 30 minutes of pushing I realized I had to throw in the towel on this metal hole saw. It was starting to work, but just an embarrassingly small amount. I just couldn’t get enough pressure into the wall against the rebar. Short of quickly framing some sort of wall behind me to push against, I realized this hole saw just wasn’t going to do the job. Well, that’s a $22 lesson of what no to use for rebar in a hole in my wall. As if to mock me, the DIABLO left a nice red ring around the outside of the hole as if to remind me of the time and money I spent on something that didn’t work.
Time to get serious
I am now hours into this project with research and effort and money and going NOWHERE fast. I reached back out to some friends asking again for leads to someone who may have a cutting torch. I even called the tool rental place and they said because of the danger factor, they couldn’t rent out their shop’s acetylene torch. I did get a lead for someone nearby though so I made the call. Dan (also known in this story as my guardian angel), DID in fact have a cutting torch, but after a few quick minutes of explaining to me how rock (including concrete) explodes and shoots projectiles when it reaches a certain temperature, my dream crumbled realizing the cutting torch was no longer an option. He did however say that he had an option for me. Although he doesn’t have the 2.5" size I am needing, he has a specialized spinning core drill that has a diamond particle bit on it. It connects to a water hose for lubrication. He said it will definitely cut through whatever I’m needing to cut through, but that it was going to wear me out because I would be applying pressure rather than letting gravity do the work. Little did I realize what he meant.
Starting To Work!
It’s working!!
Finally after about 20 minutes of solid pushing into the hole, a big chunk of the rebar came out! Because the core bit is only 2" wide, I have to move it over the left and drill out the remaining rebar. Long and tedious and very difficult yes, but working, YES!
Slipping
With the rebar gone on the right side, I have to hold the very heavy drill up in place and push hard against the rebar on the left, but it keeps rotating back into the hole from where I was cutting on the right side. After around 30 more minutes of just brute pushing and readjusting and pushing- I’m finally through!
I’m through the rebar!
I can’t adequately express just how happy (and exhausted), I was when I realized the rebar was gone — enough to go back to using the hammer drill and carbide tip saw. Let’s just say, if this would have been a movie scene, there would have been some slow motion and epic music happening.
Finishing The Hole
So, I’m past the rebar and things are going well. I will never again complain about a hammer drill being difficult to use (compared to a water lubricated core drill), when suddenly progress stops again…..NO! please no more rebar!!
I pull the hammer drill out and discover that the drill won’t move forward because the pilot bit loosened and was preventing the hammer drill from moving further into the wall. I grabbed some pliers and pulled the bit out and really clamped it tightly back into the hole saw. A few minutes later the same thing happens. After two more times, I feel the wall give and I am FINALLY through the wall!
Exhausted and Elated
Well, it’s done! I can’t thank my guardian angel friend enough for making his awesome drill available to me.
As much as I would love to sit and revel in the completion of this now 10 hour journey, it’s time to move forward. As I look down the hole, the slope looks great and the position seems to be perfectly placed — and still allow the wall framing to be where it needs to be without covering up the hole at all (double success). But, now I also realize I’m staring at some dirt. I will have to pull back the gravel and dig the level down just a little. I am also really liking the idea of continuing the drain over towards the window well. To be determined after install. But for now. I’m done with this part of the project! When It’s time to install the wall unit, I’m going to have to decide where to put the condenser outside. It could be right next to the drain, or I can place it to the left of the existing condenser for my home.
