John Sayers' Recording Studio Design Forum Archive

Keith:

Not only did I not have stairs to use to get the rocks out (I had to pull the stairs up to the 'draw-bridge' position), but there was not the most room in order to maneuver shovels and other tools... this was especially true as the hole got deeper (but couldn't get any wider)...

I actually had to lift the big rocks by hand to the outside ground; the smaller ones were loaded in a pail and raised to a wheelbarrow just outside.

Yes, the bad side is that there's lots of glacial till and erratic stones (granite, etc.) that get in the way of digging, but the good side is that the support of the ground beneath has GOT to be pretty strong....

If it's like that for the whole floor, I would think that I have little worries about the weights of the walls I will be putting on it....

Now if I show the 'hole', who's to say that the rocks didn't come out of it?
Or, for that matter, if the this is actually my pile of rocks... or even my house!?
At some point, ya gotta just have trust and faith...
Besides, what motivation would I have to fake this sort of thing? LoL.

But posting hole pics might show what I mean by being amazed that these rocks could all fit in the hole....
(Of course, I will be posting new rock pile pics in the event of more 'progress', since the hole still needs some digging, and I wouldn't raise the 'drawbridge' again until I did more digging (or a problem arose))....

K

sharward wrote: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

Just as a notation (to myself?), I had spoken to a guy at Dietrich Steel in Lunenburg, MA, for the purpose of ensuring that they get the order right the SECOND time...

This is what it's supposed to be:

40 pieces x 12 feet, 18 gauge 400S162 (4 by 1 5/8 inch) unpunched studs (back-to-back ceiling joists).
4 pieces x 14 feet, 16 gauge 800S200 (8 by 2 inch) unpunched studs (for headers).
4 pieces x 14 feet, 16 gauge 800T200 (8 by 2 inch) track (for double-boxing lintel/headers).
22 pieces x 12 feet, 14 gauge 362T125 (1 5/8 by 1 1/4 inch) track (tension flanges)
4 pieces x 12 feet, 18 gauge 400T162 (4 by 1 5/8 inch) track (for blocking, compression flange support pieces).

This is only to frame the inner leaf ceiling and for the 'extra' support joist flanges (btw, this was designed by a structural engineer)...
the wall framing is still planned to be of PT SYP lumber...

K

Be sure to use galvanized fasteners (nails, screws, brackets, hangers) since you'll be using pressure treated lumber for your walls. This will reduce (but not eliminate) the amount of corrosion on the fasteners that would compromise their integrity over time.

--Keith

Tru dat.

I guess there is specific grades of corrosion resistant hardware to use in specific locations and conditions with PT...
I'm thinking the conditions depend alot on the moisture that would be expected (e.g., outdoors and submerged would be the most conducive to the formation of the corrosive solution of the PT treatment chemicals).

This may also be an essential reference when combining steel with wood in a structure:
http://www.huduser.org/Publications/PDF ... lguide.pdf

sharward wrote:Be sure to use galvanized fasteners (nails, screws, brackets, hangers) since you'll be using pressure treated lumber for your walls. This will reduce (but not eliminate) the amount of corrosion on the fasteners that would compromise their integrity over time.

--Keith

[the following was copied from posts on Sharward's thread; didn't want to continue hijacking]

knightfly wrote:

In the case of an inner wall supporting separate ceilings, a typical 12 foot wide room with ceiling joists supported on stud frames and 2 layers of 5/8 wallboard on one side of each frame (wall and ceiling) will exert about 115 pounds on the floor per lineal foot of wall (half the ceiling weight per running foot and ALL the weight of 1 lineal foot of the wall) - This equates to about 345 PSF, considering 2x4 plates.

Steve:
Thanx for the insight. I had previously done similar calculations for my room project, and they seem to concur with yours (or at least be in the ballpark, due to some design differences)...
My biggest fear was not really the linear weights of the walls supporting the inner-leaf ceiling, BUT the 2 point loads of the lintel/header posts (the header effectively replaces the fourth wall), each of which would potentially carry 1/4 of the entire ceiling/joist (however, the lintel/header is designed to be able to carry more than the whole ceiling -- as a safety factor).

knightfly wrote:

A typical car weighs around 3000 pounds and puts ALL its weight on 4 tires, each of which has a "footprint" of about 50 square inches, or 0.347 square feet, for a PSF point load of around 2100 pounds.

I know Rod has cautioned against using this logic, and I'm not against "overkill" - still, considering the above comparisons it doesn't seem like a problem.

I think your point here is: that the tire foot print exerts a far greater localized load on the floor than any element of the room ever could -- and so if the car hasn't broken the floor up, why would the walls of the room? Is this correct....
I would agree with that (except I'm a bit wondering about whether the tires being 'softer' is any significant factor over the 'hard' edges of the wall bottom's?)...

knightfly wrote:

...possibly using DOUBLE sole plates to spread the point loads of individual studs a bit.

I had proposed at least doubling the base plates for that very same reason... How effective would this be for, say, the point loads of the header/lintels?
(And with people adding up to 3 layers of drywall on a leaf, I would think that it almost should be a matter of course to use 2 baseplates, even just for the stud point loads, no?)

Other ideas I thought and proposed (with some agreement by the PE) to spread the load were:
to use long thick gauge steel plates under the lintel/header (on top of the top plates); nesting the top and/or bottom plates in heavy gauge steel track, for a considerable length of the wall; using diagonally placed cross-bracing alongside the posts of the lintel....

knightfly wrote:

Point is (if there is one) this crappy slab has been there since 1975 and has settled/cracked/been loaded with more weight than my interior walls will exert - so double sole plates, possibly inner walls with inner ceiling joists (if I rip off the old roof) and concrete FixAll for the cracks, and I doubt very much if I'll be slab sawing/pouring new footings down the center of it at this time.

Steve, I'm not sure I get what you're meaning?
Do you mean that you think the slab is plenty strong enough, or is it that you don't care if it lasts, or can't be bothered to do footings, etc.?

knightfly wrote:

....Are you saying that your lintels (2) will be supporting an entire wall on one side with a ceiling resting on top, or what? STeve

The lintel/header would only be supporting one end of the ceiling joists (with its layers), with no wall at all (except to cover the lintel itself); the opposite side would have a full stud wall to carry the joists...

There will actually be 2 lintel/headers; the other one would be similar, but the span of the joists, and the span of the header would be significantly shorter...
The reason for the lintels is to divide the length of the room in 2 pieces, and allow it to remain as one open room isolating the entire inner ceiling from the structure above (the lintels would skirt or chase the centerbeam and the main HVAC duct of the ABOVE floor (not the studio-room)).

The 'big' lintel would be 12' 1" long, and be supporting about 11' 6" long joists; It's going to be two back-to-back 16 gauge 2 by 8 inch (actual) steel studs, boxed with two 16 gauge 2 by 8 inch tracks, and a 2 by 4 inch track as extra compression flange (and possibly one as a tension flange too)... So, it's in effect a double-boxed header.
Header span tables have shown just the back-to-back assembly to be good for 411 plf, at 12 foot length; this means it would safely hold 12 x 411 = 4932 pounds (far more than enough).
Actually, that's quite conservative, since it's simply only based on double the values for a single member; joining back-to-back more than doubles the 'true' capacity (according to an American Iron and Steel Institute article from 1997) due to the creation of an 'I' shape which greatly helps support the web and flanges; forming a double-box increases strength further.

Not really worried about the steel holding the ceiling;
I am worried about how to get the weight to the concrete floor and avoid major point loads....
The PE said "I wouldn't do it that way; I would make footings for posts", but also that it "may be okay without it too -- at least for a long time..."

I think what has been scaring me is that I've been perhaps 'over estimating' the amount of weight that would end up on the lintels, and eventually making it to the concrete...
In reality, it would seem, the lintel would only be carrying half of the weight of the ceiling (with the opposite end wall holding the other half), but I wanted it to be strong enough to carry the whole thing -- for added safety factor.
So, each lintel/header support would really be carrying 1/4 the weight of the ceiling....

I could add a center support to the lintel/header to reduce that to about 1/3 I suppose?

God, if I knew that the floor concrete and substrate below it are anything like what the sump excavation revealed, I wouldn't have an ounce of worry...

K

Structural steel was delivered today....
All was -- this time -- correct, EXCEPT that the 2 by 8 joists for the header/lintel were punched-out (so I sent them back .... I will call Dietrich again and find out the difference in header load specs when there are perforations (the charts by SSMA only refer to un-punched members)).

My main thoughts now are focusing on whether I should construct footings for the lintel columns...
This is what the engineer had mentioned a few weeks ago...
I wish there were some way to 'see' beneath the concrete floor in those areas to find out what's there for substrate (if it's like what I ran into for the sump pit, I would have no worries about strength)...
It kinda sucks that it has to be dug up to see if was okay to begin with!

ALSO, considering bolstering the centerbeam for two reasons:
first, to eliminate some or most of the lally columns (there are 4 now, at 8 feet OC); second, as a provision for supporting a second story...
This might mean flitching, or certainly using some sort of steel... and possibly putting in a new footing for a new column (one in the center of the span, at 20 feet?).

Aside from all this, I've got other concerns about things not pertaining to this project or the house -- so all is fairly on hold till I resolve them, and that will also give me time to carefully consider the options for the project...

K

Luftweg wrote:My main thoughts now are focusing on whether I should construct footings for the lintel columns...
This is what the engineer had mentioned a few weeks ago...
I wish there were some way to 'see' beneath the concrete floor in those areas to find out what's there for substrate (if it's like what I ran into for the sump pit, I would have no worries about strength)...

It kinda sucks that it has to be dug up to see if was okay to begin with!.

Oh man... ...that does suck.

The only way to know for certain would be to build it. Anything else would be "assuming" and we all know what that means...

Luftweg wrote:. . . I've got other concerns about things not pertaining to this project or the house -- so all is fairly on hold till I resolve them, and that will also give me time to carefully consider the options for the project...

I hope everything is alright, Luftweg...

--Keith

Tech support from Dietrich Steel called me back today....

According to what they said:
It seems that the header span tables ARE based upon punched members, BUT that they just don't say that they are... in other words, when members are NOT punched, it's just an extra 'cushion' of strength; conversely, if the members ARE punched, it is not a lowering of strength from the capacities or spans of the tables...

But no support (post, etc.) should be placed within 2 feet of any punch-out...
Alternatively, I could appropriately mend ('scab') sections over the punch-outs, from pieces of track or gauge steel...

Since I 'upped' the gauge of the steel already (in anticipation that the second delivery might also be punched members (but of course, I had asked for non-punched both times)), I think I will accept the 2 by 8's, 16 gauge s-stud pieces -- these were the only ones that still came back punched...

IF ANY ENGINEERS ARE OUT THERE AND WOULD FEEL LIKE COMMENTING ON THIS, PLEASE, PLEASE DO SO...
(I have not yet put this across to my P.E., since she is on vacay)...

Also, below is a pic of what I think my P.E. meant when we talked about bolstering my centerbeam (in order to provide strength for a second floor, and/or to eliminate some lally columns)...
The idea, I believe was to put c-section channel on both sides of the 40 foot beam, creating an 'I' beam with the wood in the middle; this would be done in partial spans; there would be 4 pieces -- 2 pieces each, of say 24 feet and 16 feet, and the 'breaks would be staggered over different lallys (so as to make installation easier)...

Anyone else every have this done before?
Surely there have been people who have had lally columns moved to make more clear space in basement rooms, no?

K

This came by UPS today; had got it for a really good price on eBay
Here is the 'real deal' sump pump...
A new Zoeller M98...

Eventually, 2 of these will go into EACH of the 2 sumps -- 4 total....

Even though it has a float, I will be converting them to 'manual', in order to be run off of a double-ball float 'rail' system -- this allows almost infinite, and separate adjustment of on and off points... a third float will be the over-level alarm (in that rare even that both pumps simulataneously fail, or back-up power sources are depleted, or water influx exceeds both pumps capacities, MULTIPLE cable failures, or even stupid problems -- like disconnecting things and forgetting to reconnect))...

My hand is not small; the pump is pretty big in size actually, and heavy too...

I'll bet that thing weighs a ton!

OK, maybe not a ton... But heavier than a ham sandwich!

--Keith

Yes, so heavy I didn't even wanna put it directly on the ceramic tile floor; after all it is cast iron...
but then again it has less fat than a ham sandwich... pass the mustard, yummy

K

sharward wrote:I'll bet that thing weighs a ton!

OK, maybe not a ton... But heavier than a ham sandwich!

--Keith

So, here it is:

One of the lurking issues that I've been hashing around has been moving the center staircase in my basement...
It bisects the length of one half of the main basement (there is another basement section on an 'el' to the main), and would border an interior outer-leaf wall of the studio.

At first I thought moving it would be a daunting task that might no be worth it (low or negative risk/benefit ratio)...

But, moving it has some items of definite merit:
1.) it would open up an entire 40 foot span of the basement, allowing the studio to be much larger, and to even have it double as a home theater.
2.) it would maintain a full longitudinal access to the basement from an existing window (the other option would prohibit full-length access from 2 basement windows).
3.) it would allow the air-lock room to be a bit larger, and would remove any windows from the inner studio room (better isolation; less dependency on the window's soundproofing result), AND would in fact only require one window within the whole studio/sound-lock.
4.) it would also greatly open up the above floor's room and entry-way (a living room and a parlor).
5.) it would importantly preclude the need for the steel header/lintel system to skirt/chase/soffit the centerbeam and main HVAC duct of the above floor. BUT even more importantly would eliminate any worries about the lintel support columns point load impingement on the concrete floor slab.
5.) furthermore, in eliminating the 'chase' of the beam and HVAC duct, it would allow a consistent, fully-code ceiling height throughout the room, and negate the need for footings of the lintel support columns.
6.) would allow the basement walk-out entrance area (and its own staircase) to be less impeded and open with the remainder of the basement.

Now, closing up and moving the stairwell has some work issues:
1.) shoring up old tail joist end in order to install full-length joists from centerbeam to sill (not a big issue; just make a temp bearing wall under it, no? we're only talking about 3 feet.)
2.) shoring up the joists and floor in the area where the new stairwell will be, so that parts of some joists and the floor can be safely cut out (again, temp bearing walls?)
3.) installing subflooring and MATCH white oak finish flooring (with existing white oak) over the new joists.
4.) constructing new staircase: headers where needed (all joists are doubled anyway, b/c they have been sistered); design? (straight, reverse, circular, spiral? landings?).
5.) tearing down old stairwell walls, and building new stairwell walls (the new walls would be IN the basement and not on the above floor as it is now -- yet another benefit for the main floor?).

Alas, I would have to 'eat' the cost of the header/lintel steel, BUT I'm figuring I might be having places to use those on the proposed second floor (in a mezzanine to a cathedral ceiling section? hmm?)... then again, if I choose not to pursue moving the staircase, the steel would then be used -- as originally planned.

Anyone ever relocate a stairwell and staircase?
Any ideas, advice?

And (for Keith) yes, I will have this gone over by the P.E., and would have the work be 'Permitted' by Inspectional Services.

K

Very interesting... And complicated. Without drawings, it's hard to visualize. I'm sure you'll have to make some drawings at some point, so I'll look forward to seeing them!

--Keith

Tom,

In reference to your expertise on the subject of keeping basements dry. I think it's great to have you here offering help.

Many of us are in similar situations, building studios in our basement. I wanted to ask you what effect condensation has in an otherwise all dry basement.

I have a new house with poured walls, footing drains and "rubberwall" sprayed on the outside of the foundation. But last year before I bought my dehumidifier, there was water on the floor on the inside corner of my basement, sweating pipes and such. With the humidifier there this year, there is none.

My questions is what effect does condensation play when finishing the basement floors and walls on the unconditioned space. ie. the air space between the inner wall and outer concrete wall and also the floor, assuming I put some type of laminite down.

I'm not TomVan (see 'Lost Studios in Portland' thread); he had posted here with respect to my questions on the basement concrete...

I may not have any answers for you, but I do have some comments...

peteys wrote: I have a new house with poured walls, footing drains and "rubberwall" sprayed on the outside of the foundation. But last year before I bought my dehumidifier, there was water on the floor on the inside corner of my basement, sweating pipes and such. With the humidifier there this year, there is none.

I'm sure that you also have a vapor barrier beneath the slab?
Is there also a capillary break between the footing and the walls?
Was this condensation present mainly only in the warmer, humid summer months?
Do you have rigid insulation on the outside or inside of the concrete?

Anyway, as you probably obviously know, when the warmer, more moist outside air makes contact with the cold surfaces of the concrete, the moisture condenses on those surfaces, which is why you bought the dehumidifier...
Interestingly, I have read in a few places that having a dehumidfier can actually 'pull' vapor/moisture from the outside, through the concrete, due to an increase in gradient between the moisture on the outside and inside.
Supposedly, this can increase efflorescence and spalling...
(I think the point of this idea is mainly that you should additionally pursue other means to decrease moisture from GETTING into the basement, but not to avoid the use of a dehumidifier).

peteys wrote: My questions is what effect does condensation play when finishing the basement floors and walls on the unconditioned space. ie. the air space between the inner wall and outer concrete wall and also the floor, assuming I put some type of laminite down.

Ahh, this has been a question for me as well...
From what I have learned, there are 3 moisture sources to consider here: first the condensation FROM the air, second the vapor coming through the concrete INTO the air, and third any seepage that would occur due to rainwater, groundwater, or surface runoff (that might overload or avert your drainage tile system).

Even though you have some sort of dampproofing or waterproofing on the outside of the foundation, my guess is that there would be still some vapor movement through the concrete and into the basement... of course, I really will defer that to TomVan, since he is the expert here...
But, my point is -- from what I have researched and read about -- no waterproofing system seems to be, or remain, 100% competent forever and/or under all situations.
(Concrete can crack and settle, drain tiles and pump pickups and discharges can clog, outside grading can change, gutters and downspouts and pump motors can fail...)
[For example, a friend of mine has a house, built in the late 90's; this was a construction that utilized all the latest (radon systems, sump, draintile, insulated, etc.); the concrete wall has already developed a full, separated crack from the top to the bottom...
In contrast, my house, made in 1959-60, has never had any such cracks in the basement walls (I’ve looked at the walls very closely) yet it has little or none of the 'modern' things that my friend's house has (BUT of course, that doesn't mean that we have never had any water issues here)... on the other hand, I do have hairline cracks in the floor slab – in the areas where it had been dug for the sewage service (house originally had a septic tank).]

NOW, about the 'dead air' spaces and vapor moisture....
It seems there are things here:
One says that you want to allow moisture to travel IN through the concrete and into the room;
The other says that you want to concern yourself with preventing the inside moisture from reaching the concrete walls...
Actually, still another seems to say that both are to be considered...

The problem is, it would seem that you can't use true vapor barriers and account for both situations -- at least if your dead-air space is 'locked-in' everywhere.

If you use a vapor barrier under the inner-wall surface, you will block condensation from the inside air on the concrete wall surface;
But could that barrier block vapor coming through the concrete from dissipating into the room -- and, IS this a problem if there is a sufficient air gap, or if you are fire-blocking from the above floor, can this allow vapor to vent somehow, somewhere and still maintain isolation?

I tried to find a paper I had read that talks about the problems with 'overuse' of vapor barriers, and supports the use of vapor retarders... not just in the basement, but in other areas of the house as well -- particularly in mixed-climate regions...
So, the concept is to slow the vapor moisture migration and not to stop it.
This may be the best compromise, I don't know...

But TomVan had recommended that I use a product on the concrete floor that was a cementitious 'moisture reduction barrier' or MRB, that is made by Mapei.
This reduces vapor through a slab a great deal, but still allows a certain percentage through in order that it doesn't 'build up' below that surface and ultimately separate it from the concrete.
On the walls, he recommended something like Thoroseal.
Of course, I believe he also said that any (non-moving) cracks or gaps should be chased, dovetailed, and filled with an epoxy or urethane.

Then again, remember, I probably don't have a vapor barrier below the floor, like you might, nor anything substantial on the outer surface of the walls either... so your situation might be different, and your dead air space 'needs' might then be different.

Whatever you find out, please post about it, so that others (me especially ) know...

thanx,
K