Bellyacres Productions - Basement Studio Build

[DanCostello]

Hey guys, I figured it was about time to start a thread for my build. The goal is to convert a portion of my basement into a 5.1 control room + vocal booth. The CR would double as a live room somewhat larger than the booth - I do sound design and most of my recording is more like what you'd think of as foley, and I'd be recording myself most of the time. So, I need pretty good isolation, but not a bunch of rooms or space for a whole band.

I'm still in the process of ripping out the stuff that's currently in my quasi-finished basement, so I don't have much to show for pictures yet. But one of the first things I'm going to have to tackle is leveling out the concrete slab floor. The ultimate goal for the floor is to have a polished concrete floor throughout the entire studio. There are a lot of things I like about having a concrete floor - I like the sonic properties of it (both for isolation and for recording foley); I like that it's easy to clean; I like that I don't lose any headroom with it (I'm 6'5"); and I like the way it looks (I'm thinking of a hipster/industrial style with reclaimed wood)

My tentative plan for the floor is to use a self-leveling concrete and (assuming I don't hire someone) to do the floor in chunks (i.e. build a dam around a portion of the room, level that, then move the dam to the next portion and level that, etc). I'm doing it in chunks, because from what I understand, you have to move quickly w/ this stuff and I don't have enough friends to help me get the whole thing down in one shot.

The total area of the floor to be treated is about 500-600 sq ft and the total variation in floor height is about 1.5-2", which appears to be on the high end of (but still within) what most of the self-leveling concrete allows.

From reading posts on the board and then reading information available elsewhere, it seems like the options for self-leveling concrete have improved over the last 10 years or so, with more options available now for product that can be polished and act as a wear surface instead of merely being used as a substrate for other flooring materials.

I guess my question is whether or not any of you have any experience doing this and if you have any pointers for me? One of the concerns I read on an older thread was that the self-leveling concrete doesn't take well to being drilled into and has a tendency to crack when drilled. Does anyone know if that's still the case? I haven't gotten so far as planning my wall construction yet, but I have seen wall designs on here that require drilling into the floor, so I don't want to shoot myself in the foot.

Thanks,
-Dan.

[Soundman2020]

Hi Dan, and Welcome!

I guess my first question would be: Why is the floor NOT level? Clearly, it was built that way, and there must be a reason for that' I'd check with the original architect, or perhaps local contractors, to find out why it is sloped, and see if it is safe to level it. That is usually done when water is expected in the basement for whatever reason, and it is often associated with a sump or drain at the low point. First check on that, before deciding if you can level it or not.


- Stuart -

[DanCostello]

Hi Dan, and Welcome!

I guess my first question would be: Why is the floor NOT level? Clearly, it was built that way, and there must be a reason for that' I'd check with the original architect, or perhaps local contractors, to find out why it is sloped, and see if it is safe to level it. That is usually done when water is expected in the basement for whatever reason, and it is often associated with a sump or drain at the low point. First check on that, before deciding if you can level it or not.


- Stuart -

Hey Stuart,

Thanks for the welcome!

It's not level because it's an 80+ year old Baltimore rowhouse and in the 1930's, basements weren't used for anything more than storing coal and asbestos. It's not even sloped per se - it's just wobbly. There is a sump pump, but the water only kinda-sorta drains towards it. There have been a couple times when water's gotten in down there - either from a leaky pipe, a failed sump pump, wall seepage, or other reasons. Trying to investigate the source is a challenge, because the water will run in different directions and pool in the low spots and by the time you find the water, the only pools that are left are nowhere near the original source.

[Soundman2020]

That's sort of what I expected, Dan: If there's a sump pump, then there is a water problem: You said it yourself: "There have been a couple times when water's gotten in down there - either from a leaky pipe, a failed sump pump,...". The sump pump is there to remove water that accumulates either on the slab, or under it, or from foundation drainage. If water accumulates when that pump fails, then you have problem. It means that water is always present, but you normally don't notice it because the sump pump is doing it's job, You only notice it when the pump stops doing it's job, and the level rises.

Your first order of business, before you can think of leveling it, is to find out where that water is coming from, and stop it. You most definitely to NOT want to build a studio on top of a floor that occasionally gets wet!

I would suggest that you should call in a local expert and get your basement fixed so it no longer has a water problem, then think about how to level the floor after that.

To determine if you have an actual slab problem, here's a quick test for you: Get a piece of clear plastic sheeting, and cut out a largish square, maybe 6" or 8" on each side, and carefully duct-tape it to your floor, at a place that is reasonably smooth and even, and that you have swept clean. Tape it down around the edged so that it is sealed to the floor as well as possible. Leave it there for several days, or weeks, and check it occasionally: if you see any water under it at all, such as droplets of condensation, then you have a problem that MUST be fixed before you can build the studio.

You cannot fix this by just sealing the floor water-tight from inside the basement: That would be even worse, as water is immensely strong and un-compressible: It will force its way in. In addition to damp issues, hydro-static pressure can cause your slab walls to spall, crack, or flake. In extreme cases, it can cause structural damage.

This is probably not something that you can fix yourself with common DIY solutions. Better call in the professionals to do this par for you. They might even be able to level your floor at the same time as they solve the water issue.

- Stuart -

[DanCostello]

That's sort of what I expected, Dan: If there's a sump pump, then there is a water problem: You said it yourself: "There have been a couple times when water's gotten in down there - either from a leaky pipe, a failed sump pump,...". The sump pump is there to remove water that accumulates either on the slab, or under it, or from foundation drainage. If water accumulates when that pump fails, then you have problem. It means that water is always present, but you normally don't notice it because the sump pump is doing it's job, You only notice it when the pump stops doing it's job, and the level rises.

Your first order of business, before you can think of leveling it, is to find out where that water is coming from, and stop it. You most definitely to NOT want to build a studio on top of a floor that occasionally gets wet!

Thanks, Stuart.

Yeah, I'm pretty familiar with basement water issues. The house I grew up in had terrible water problems (both through the walls/floor and backflow through the sewer). We had a bentonite injection and french drain installed early on, but the backflow problems took longer to sort out. It got so bad that one time we called the fire dept out to bring over an extra sump pump, they showed up with a friggin fire truck and still couldn't keep up with the backflow. Getting a call from the fire chief in the middle of the night was enough to get the guys at the DPW to stop ignoring us. Then at different points, my dad and I both worked at a basement waterpoofing firm run by my best friend's dad.

In my current house, I've already identified the sources of the water:

1.) Above-grade leak in the front of the house, next to a window opening. This only leaks when it rains really really hard for an extended period of time. I put a temporary patch in last summer that seems to have held up so far. When I do the full build, I'm going to brick up the windows completely (assuming that's legal, which I would hope it would be, since the current windows aren't remotely usable as an egress). Even if I can't brick over the windows, a more legit patch is on the to-do list.

2.) Pressure release valve on the furnace. Because why not just have your furnace empty on the floor?

3.) Beneath the house. This does show up in the sump pump - this was how I found out that the sump pump needs maintenance - because the float valve doesn't trigger correctly and if you don't hit the switch by hand, it won't trigger and the sump will overflow. I've seen water in the sump 2-3 times in the year I've owned the house and it's rained a LOT. A repair/replacement of the sump pump is also in order.

All of the walls have been painted with waterproofing paint and I plan to touch that up as part of the reno. Fortunately, I'm in the middle of the block, so my neighbors act as something of a buffer against leakage. That means only the front and back of the house and the floor are at risk of leaking. I won't be touching the floor in the back of the house, which only leaves the front wall and front half of the floor to really worry about with respect to the build. It's surprisingly dry given the amount of rain we get and fortunately, the water problems we've had have been VERY minor compared to the stuff I'm used to. I had the water heater die in an apartment about 10 years ago that left about 3" of water across the entire basement. The worst I've had here are a couple small puddles.

[DanCostello]

This project has been going slowly, but it's been going. Demo is done. Asbestos pipe insulation has been removed and replaced with fiberglass. I'm in the process of scheduling brick & concrete people to fill in the windows and level the floor. I've got some ideas about what to do for A/C, but to check the feasibility of that, I'm going to get a consult from my HVAC guy when he comes out to do the annual maintenance in the spring.

Here are screenshots of the SketchUp model of the basement as it exists currently. The studio will be everything in the top-down view left of the water heater and sump, minus the stairs. The control room will be the space marked as 15' 6 7/8" x 16' 6 13/16", and the vocal booth is the space that's 8' x 12' 2". Not shown are the ceiling heights - the joists are about 8' 1.5" high in the control room and 7' 1.5" in the vocal booth. Once the floor is leveled, it'll be about 8' in the control room and 7' 1" in the booth.


Once I flesh out a rough idea of the design, I'll start a thread in the Design forum for that and leave this thread for construction stuff.

original_top.jpg

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[DanCostello]

Anybody have any opinions on the difficulty of installing resilient channel vs the difficulty of installing RSIC clips? At the very least, I'm going to have to use some sort of isolation brackets on my ceiling, just because I don't have the headroom needed to hang a separate set of joists. In investigating RSIC clips, I came across this thread featuring everybody's favorite diy home studio author where the merits of RC and RSIC are debated. If properly installing RC is really as fussy as some of those guys make it out to be, then I could see it being something I would either obsess over and nail perfectly, or something I would obsess over and totally bone.

My back-of-the-napking guesstimate is that the RSIC clips might be another $5-600 (or about 38%) more expensive than the RC-2. That's not trivial, but it's also not a huge deal relative to the total cost of the project, and might be worth the insurance, particularly if it performs better even when RC2 is installed perfectly.

Thoughts?

[Soundman2020]

Anybody have any opinions on the difficulty of installing resilient channel vs the difficulty of installing RSIC clips?

I would go with the RSIC clips plus hat channel. Slightly better overall isolation, and less chance of screwing it all up with a stray fastener.


- Stuart -

[DanCostello]

So, at the top of my basement walls, between each of the joists are some bricks that do... I'm not really sure they do much of anything except look bad and get in the way of me accessing the wiring on the first floor. They don't hold up the floor. Some of them might serve as a sort of vertical bracing block for the joists, but many of them are either so deteriorated or so poorly installed that they don't serve that function, either. Here's an example:

wall_bricks.jpg

The section on the left is fairly representative of the sections in the best shape. The one on the right is one of the worst ones (i.e. half of it is gone)

What I'm wondering is how best to seal up these voids. If this were a merely a large brick wall, I would use some kind of rendering cement to render the whole wall. But I'm skeptical that that would do well at filling the voids between the brick and wood. Would I be better off just covering over the voids with wood and drywall and sealing the edges with some caulk?

-Dan.