John Sayers' Recording Studio Design Forum Archive

That looks like an awesome plan. I'm of course no expert at this -- living in this part of the country, as I can count on one hand the number of residential basements I've been in (one of which was out of state), and I didn't even know what a sump pump was until I started hanging out on this forum! But I do recognize, from first-hand experience, the power of even a small amount of water to cause major damage. I'm also an IT guy that works on systems with "fault tolerance" and "redundancies" -- and it seems you're definitely on the right track in designing a system with multiple points of failure and accommodation for those failures.

I have a feeling that whatever plan you end up finalizing will become the gold standard for reference on this forum.

Perhaps you can share this plan with some licensed basement waterproofing contractors to get their two cents as well. They may think of something you haven't. Or they'll shower you with compliments and that feels good.

--Keith

Ahh, but here is a version, with 4 AC motor pumps....

There are advantages to ac motors over dc motors (one reason that I didn't at first consider the dc pumps)....
Of course, the inverter is required again...

Interestingly, ac motors are more efficient...
On Boston's 'Red Line' subway, they bought a bunch of trains several years ago that actually have ac motors, even though the third rail is dc (the older trains still run on dc)...
So, this means inversion of the power to ac on board the train; apparently they considered it worth it to do it that way...

The other benefits of running ac pumps are:
I would be able to use smaller gauge and longer wire, not needing to worry so much about voltages drops and power losses (my sumps are 40 feet away from each other; you CAN run 20 foot battery cables, but they have to be very thick and there WOULD be power losses);
Of course, I could opt to have TWO battery chargers and place a single battery right next to the sumps...

So if I go ac, I would not need to keep the batteries as near as possible to the pumps.
Plus, being all ac pumps, they could be switched to run through different circuits, if needed, and can be rotated with each other.
If they are more efficient, any power losses of the inverter might be more than made up for....

K

Halo:
Can someone try to explain what is going on with this scenario:

If you have seen my earlier posts on the 'studio-room in boston area' thread, you noticed that I 'sistered' the joists of the floor ABOVE where the studio will be....
I did this because I will be adding mass in those joist bays for the outer-leaf ceiling of the studio, and I wanted to strengthen them to ensure safe support...

What I have noticed is this:
When I knock on the doubled joists, I hear a subdued thud...
When I knock on the joists that have NOT been sistered, I hear a much higher pitch and a 'ring' type reverberation...

There is very little or no reverberation at all with the sistered joists....

What's up with this?...

What I'm thinking is that the mass of the joists is doubled, and so the pitch should be halved?...
But of course this is a simplistic model, since the floors are also stiffened (deflection decreased) although the floor loads are still about the same...
But again, if things are stiffened, then that would mean an increase in pitch, no?... Yet, what I'm hearing seems to indicate a lower pitch (maybe the stiffeness increase is not as great as the doubling of mass increase?)

So, I'm also thinking that the vibration of the joists is of less energy -- not just a lower pitch...

Am I on the right track here?
Is this good or bad.... or a mixed bag?
If the pitch is lowered, it could be bad because higher pitches are easier to block?
Although if the energy of setting it in vibration is lowered, maybe it balances out?

Gonna see if I can verify the pitch and damping a little bit more closer; maybe I'm mistaken.....

thanx,
K

Pitch with sisters being lower and QUIETER is a good thing; if it were lower and LOUDER it would be bad. Your second leaf will presumably differ a LOT from the first, so shouldn't let any of the primary resonances of the upper leaf through.

Keep in mind that, although low freq's are harder to stop, the lower they get the less we hear them; until at around 50 hZ, the threshold of human hearing is around 55 dB... Steve

Yes Steve,
The inner leaf ceiling will actually have back-to-back steel 2 by 4's (162-S-400 20 gauge structural; with that, the shape of the members are 'I's' 4 inches tall and 3.25 inches wide, with a combined 14 'gauge' thickness), this is much different than the wood...

K

knightfly wrote:Pitch with sisters being lower and QUIETER is a good thing; if it were lower and LOUDER it would be bad. Your second leaf will presumably differ a LOT from the first, so shouldn't let any of the primary resonances of the upper leaf through.

Keep in mind that, although low freq's are harder to stop, the lower they get the less we hear them; until at around 50 hZ, the threshold of human hearing is around 55 dB... Steve

The delivery truck came today to bring the structural steel....

The order was WRONG!
I'm lucky I just happened to be home when they called to say they were coming; I sent the truck back without a single piece unloaded.

I had ordered 'S' section studs for the inner ceiling and header/lintels (to skirt the house's wood center beam).
I specifically wanted them un-punched (as span calculations were based on un-punched members, and I don't need punches anyway)... but they came punched!

Also had ordered 14 gauge track (for this extra tension flange thingy); it turned out to be only 20 gauge!

The manufacturer was Dietrich in Lunenburg, MA...

The mistakes on the order were clearly shown on the manifest and/or bill of laden.
Could also have been other errors, but I didn't even get that far... just sent it all back...

(btw, I may take this opportunity to change part of the order from the 20 gauge 4 inch studs, to 18 gauge -- for a higher SF... will throw this idea across to the structural engineer next tuesday... of course it'd be stronger, but the important consideration would be that the linear foot weight will go from 0.94 to 1.21 lbs.)

Sheeeesh.

K

That's terrible!

Gee, I wonder if that supplier was involved in The Big Dig out there...

(In all seriousness, what a tragedy last week. )

--Keith

The whole thing (re: Big Dig death) should have never happened...
Did you see Gov. Romney on TV, visibly p*ssed?

Here's a discussion about the event on an engineering forum:

http://www.eng-tips.com/viewthread.cfm? ... 632&page=1

sharward wrote: ...wonder if that supplier was involved in The Big Dig out there...

(In all seriousness, what a tragedy last week. )

--Keith

Well, I took a little break from studying to dig the second sump pit under the basement entrance steps...

At first I thought I would be able to break through the floor concrete easily enough, and pry the few inevitable rocks out of the hole while digging the 30 inch pit...

Was I ever wrong.
I couldn't barely touch this stuff with a sledge, it was so solid...
Now I know why the unknown person long ago tried and gave up...
I only got to slightly increase the size of the tiny hole they dug, as I hit huge, rock after rock after rock with the 6'6" prybar I was using -- and barely anything budged.

THEN, I called out the big guns;
I rented an electric jackhammer.
Although this made a major difference, it was still slow-going...
The concrete floor layer was about 5-6 inches thick on average above the larger stones (although, there were alot of smaller about 1 to 1.5 inch stones, apparently within the concrete mix itself...
BUT, this was also poured over an immense amount of different sized rocks:
there was shale, rip-rap, boulders the size of footballs and basketballs (I'm NOT kidding) -- some parts of the concrete were easily 9 inches deep.

All these stones/rocks were packed to a tight bedding, even below any cemented areas -- almost as if it were compressed stacked stone; I still had to use the jackhammer on most of this stuff.
Currently I have gotten to about 20 inches below the floor surface, and it is STILL like this....

All I can say now is I think I have much less worries about any part of my basement floor not being able to handle the weight of the walls and inner-ceiling -- although, I suppose I may be partly in the area of the footings (yet, it's like this between the footings of the opposing walls)...

Wonder what gives here?
Is this just the way the ground was below the construction, or was this all actually made by someone?
Hope I'm not disturbing some old Native American ceremonial site or something....

About the sump pit:
It is to house 2 pumps (primary and backup, or alternated pumps with backup power for both)...
From what I've been reading, it is best to have the pit as wide as possible, especially with fixed-float submersible pumps, because this allows them to run longer (pump more water in one cycle) and cycle less (not go on again for a longer time)...
My brother (into plastics) is trying to hook me up with a plastic tank that I can use for a liner; some large size sump pits sold by companies such as Zoeller, etc., can easily cost $500... ouch.
(Bro said he might be able to get me one that he has made for an earlier work project of his, for 15 bucks, although I'll have to make the appropriate alterations to turn it into a sump liner (perforations, plumbing for radon, cables, etc...)...
Right now, I have a submersible 1/2 hp pump mounted inside a 5 gallon pale, with perforations and straps to hold the pump tightly in place inside of the pale... Over the pale is wrapped a fine screen for silt... The pale is just simply placed in the bare hole, and stabilized from movement with some of the rocks that were pulled from the same hole...
Had to do that because there WAS in fact a slight amount of water rise in the hole (although, to a point below the floor), AND we were having T-storms with lots of rain today....
This setup has actually been working wonderfully; the pump ejects alot of water (maybe 30 gallons?) in one activation, and the cycle interval is very long...

K

Folks, it's all a lie -- because he didn't post any pictures!

Seriously, though... Man, I sympathize with you. It sounds like your basement is on top of a quarry!

If you're using a 60 pound electric jackhammer, you may be better off with a 25 pound handheld rotohammer, which is what I used to chip away at my foundation.

Post some photos so that we can be glad it's you and not us doing that nasty work! (I'm sooooo glad I'm finally done with my digging! )

--Keith

LoL ....
I am going away for 3 days....
If I can't get up any pics tomorrow, it will likely be thursday or friday before the pics are up... for all the disbelievers...

The pit was getting a bit deep, and there was a degree of water in it, as I was entering below the current water table... I didn't know about the rotohammer tool, but I'm not sure if I should be standing in water and using any electric device. With the jackhammer, I was able to stand out of the water, either with legs splayed over the hole (sounds dirty), or standing on something non-conductive and sturdy-ish...
At this point, I have loosened things up a bit with the jackhammer and the long prybar (while periodically pumping the pit down, so I can see what I'm doing better, and not have to 'row' water in addition to moving dirt and rocks).

Btw, I DO ache a bit from this work...

K

sharward wrote:Folks, it's all a lie -- because he didn't post any pictures!

Seriously, though... Man, I sympathize with you. It sounds like your basement is on top of a quarry!

If you're using a 60 pound electric jackhammer, you may be better off with a 25 pound handheld rotohammer, which is what I used to chip away at my foundation.

Post some photos so that we can be glad it's you and not us doing that nasty work! (I'm sooooo glad I'm finally done with my digging! )

--Keith

Seriously -- regardless of whether you use a rotohammer or a stand-up electric jackhammer, or for that matter any electric tools or appliances in any area where there is the possibility of contact with water -- if the outlet is not already GFCI protected, get one of these ASAP:



Your life may be saved by one of these things. So, by "ASAP", I mean "Stop using power tools in wet areas immediately and don't resume until you get one of these."

Please see my "Protect Yourself Using Power Tools in Wet/Damp Conditions!" post (and Steve's reply) in the "Safety During Demolition, Construction" thread.

Promise?

--Keith

Thanx Keith....

You ARE RIGHT....
Must use ground fault protected circuits...
Although interestingly enough, even they might not completely protect you in all instances, such as if the entire shock current passes from the hot wire though the body and then back through the neutral...

http://en.wikipedia.org/wiki/Residual-current_device

I have GFCI's in several places around, but not nearly enough as I should!

K

Here are some pics of the stones and boulders that were pulled from beneath the floor where the 2nd sump pit is going to be.

A single 1/2 hp pump is temporarily mounted in a 5 gallon pail, which I perforated and screened, and then placed in the hole.

The hole is 20 inches wide, 30 inches long, and about average 15 inches deep -- so far (only at the spot at the base of the 5 gallon pail, the depth is about 18-20 inches)

It still needs to be dug lower -- about 30 inches total depth....

The stairs are a 'draw bridge' and I had to lower them back down in order to not tie-up that entranceway.
I was too lazy to lift them again just to take pics (I will do that when I finish the hole).

By looking at this pile, it's almost hard to believe that it came out of that size hole.... maybe a testament to just how well it was packed-down.

Is this material a good substrate for the concrete floor support?

K

So, did you do a little dance when you got that big rock out of that hole? Holy cow!

It makes me almost appreciate the heavy, sticky clay soil I had to deal with in my excavation... And I didn't have to climb stairs to get it outside!

Now let's see that hole. For all we know, you just moved some rocks around out back!

--Keith