# Doing an underground tub rough



## 907plumber (Mar 13, 2010)

So I'm getting ready to do an underground rough. Its been a long time since Ive done one. And Ive only done a few. One thing I can't recall is the tubs. I know we would frame a box that would keep concrete out of the drain area.

I can't remember if we installed the p-trap or just left the trap arm and installed the p-trap later.

Id rather do the p-trap later when i have the tub on site and make sure everything is gonna be lined up just right.

You guys have any pictures?


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## plbgbiz (Aug 27, 2010)

Stub it in, fill the box with sand, complete the trap when you rough the tub.


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## tim666 (Mar 11, 2014)

This is how we do it, install the trap and build a wooden box. After plumbing is inspected and floor relevelled they usually put the box back and most times we have to offset to the overflow


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## love2surf927 (Dec 22, 2011)

They make plastic tub boxes you can use. Just like biz said put box in place, fill with some sand, then I usually stake it with a few pieces of rebar, then tie the top on with tie wire. Obviously after the pipe is stubbed into the box, and pipe is wrapped with foam wrap. Make sure the stub is in close enough proximity so you can hit your centers with the swing of the trap. You shouldn't have to offset the overflow, it should end up touching the bottom plate pretty much.


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## love2surf927 (Dec 22, 2011)

tim666 said:


> This is how we do it, install the trap and build a wooden box. After plumbing is inspected and floor relevelled they usually put the box back and most times we have to offset to the overflow


I don't really understand this?


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## rjbphd (Feb 5, 2010)

I put the tub in first.. then tell the concrete guys and framers to be really careful


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## tim666 (Mar 11, 2014)

love2surf927 said:


> I don't really understand this?


Different ways, we install the trap against the wall where the waste and overflow would normally go. Most times we don't have the tub specs at this time so it doesn't line up 100%, when we put the ty for the waste and overflow at the rough in stage, we aim for the drain but usually have to offset to line up with the overflow


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## Leach713 (Nov 1, 2013)

tim666 said:


> Different ways, we install the trap against the wall where the waste and overflow would normally go. Most times we don't have the tub specs at this time so it doesn't line up 100%, when we put the ty for the waste and overflow at the rough in stage, we aim for the drain but usually have to offset to line up with the overflow


Most tubs are 30x60 15"center and 2"from 2x4
Or 42x60 21" center and 2" from 2x4 

That the whole purpose of the tub box is to have room for your waste and over flow and not needing to chip if offsetting is require for waste and over flow


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## Dpeckplb (Sep 20, 2013)

We stub the 1 1/2 into an 8"x 8" 2x4 with a 1/2" plywood topped box roughly centered to the print(we get specs from maax or mirorlin) and redo the print. Once the tub is there I take the sawzall and cut it out. Then hook it up then.


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## wyrickmech (Mar 16, 2013)

For a time we had to use a piece of twelve inch sdr long enough to pour a bottom of concrete under the trap. It was to seal the floor to keep bugs from entering threw the opening.


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## sparky (Jan 8, 2014)

wyrickmech said:


> For a time we had to use a piece of twelve inch sdr long enough to pour a bottom of concrete under the trap. It was to seal the floor to keep bugs from entering threw the opening.


Man that was a lot of trouble wasn't it ?? I always build a box and put trap on later myself


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## sparky (Jan 8, 2014)

tim666 said:


> This is how we do it, install the trap and build a wooden box. After plumbing is inspected and floor relevelled they usually put the box back and most times we have to offset to the overflow
> 
> View attachment 31531


I worked for a company at fort Campbell for a yr one time and this was how they did it also and it worked out pretty good.just had to 45 or 22 it over sometimes and most times they hit dead on,
But seems to me they had to be above the floor rough tubs if memory serves me right


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## wyrickmech (Mar 16, 2013)

sparky said:


> Man that was a lot of trouble wasn't it ?? I always build a box and put trap on later myself


 ya it sucked bad.


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## 907plumber (Mar 13, 2010)

Thanks for the tips guys. Just ended up rough stubbing the trap arm into the vicinity, boxed it out and will finish the trap installation when its time to set the tub.


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## plumber joe (Oct 17, 2008)

Above the floor tubs are the way to go. Put the trap in and stub up 2" pipe. I like to use a 2" x1 1/2" x 1 1/2" tee.


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## brandieboyle134 (May 18, 2014)

Clearly after the channel is stubbed into the container, and funnel is wrapped with froth wrap.


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## plbgbiz (Aug 27, 2010)

brandieboyle134 said:


> Clearly after the channel is stubbed into the container, and funnel is wrapped with froth wrap.


Do they rough in tubs in Bangladesh? See ya Elvis.


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## sparky (Jan 8, 2014)

plumber joe said:


> Above the floor tubs are the way to go. Put the trap in and stub up 2" pipe. I like to use a 2" x1 1/2" x 1 1/2" tee.


So you use a 2" trap on a bathtub when it's on a slab????


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## wyrickmech (Mar 16, 2013)

sparky said:


> So you use a 2" trap on a bathtub when it's on a slab????


nothing less than 2 in allowed below grade so yes it would be 2 in if the codes are the same as here


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## rjbphd (Feb 5, 2010)

sparky said:


> So you use a 2" trap on a bathtub when it's on a slab????


Stupid Illinois code required 4" min of any drain in slab..


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## redbeardplumber (Dec 4, 2012)

Not code here.... But I always put 2" traps...

4"..... CRAZY RJ


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## Master Mark (Aug 14, 2009)

we used to use a 5 gallon bucket for a frame in the concrete.... it always worked pretty well..

all that is required here is 2 inch going to the box then it can be reduced down to a common 1 1/2 p trap


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## 422 plumber (Jul 31, 2008)

rjbphd said:


> Stupid Illinois code required 4" min of any drain in slab..


Is that Illinois code or Chicago? I have only did that in Cook County.

Sent from my iPhone using PlumbingZone


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## sparky (Jan 8, 2014)

wyrickmech said:


> nothing less than 2 in allowed below grade so yes it would be 2 in if the codes are the same as here


Same here in ky on any waste pipe below slab but you are allowed to install 11/2" traps and vents below slab,they figured why put a giant trap on it then reduce it down to 11/2"


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## sparky (Jan 8, 2014)

Master Mark said:


> all that is required here is 2 inch going to the box then it can be reduced down to a common 1 1/2 p trap


Yes same here in ky,makes no sense to put a 2" trap then reduce it down immediately


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## wyrickmech (Mar 16, 2013)

sparky said:


> Same here in ky on any waste pipe below slab but you are allowed to install 11/2" traps and vents below slab,they figured why put a giant trap on it then reduce it down to 11/2"


we can't run any pipe below grade less than two inch even vents. There was a time where they required three inch all the way up to floor level then you could reduce to stay in the wall.


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## leakfree (Apr 3, 2011)

rjbphd said:


> Stupid Illinois code required 4" min of any drain in slab..


I've done thousands of tubs under Il. State code and under Chicago code and have never had an inspector make me use a 4" trap on a tub or shower.Sections below are dated 4/14/2014 and don't differ much from earlier versions


7: PUBLIC HEALTH 
CHAPTER I: DEPARTMENT OF PUBLIC HEALTH
SUBCHAPTER r: WATER AND SEWAGE
PART 890 ILLINOIS PLUMBING CODE 
SECTION 890.410 FIXTURE TRAPS/CONTINUOUS WASTE


Section 890.410 Fixture Traps/Continuous Waste

a) Fixture Traps. All directly connected plumbing fixtures, except those having integral traps, shall be separately trapped by a water-seal trap, placed as close to the fixture outlet as possible. A kitchen sink with up to three basins may be installed on one trap if one compartment is not more than 6 inches deeper than the other and the waste outlets are not more than 30 inches apart. (See Appendix D.Illustration A.)

b) Distance of Trap to Fixture. The developed length from the fixture outlet to the trap weir shall not exceed 24 inches, except that an interceptor used as a trap shall be located as close as possible to the fixture. The maximum developed length from the fixture outlet to the inlet of the interceptor shall not exceed 5 feet. (See Appendix D.Illustration B.) The standpipe inlet for an automatic clothes washer shall not exceed 48 inches above the weir of a trap.

c) Trap Size. The size of trap for a fixture shall comply with Appendix A.Table E for minimum size of traps. No trap shall be larger than the fixture drain to which it is connected or the drainage pipe into which it discharges.

d) Type of Traps. Traps shall have a uniform and smooth interior, and shall have no partitions or movable parts. The trap seal shall be non-adjustable. (See Appendix D.Illustration C.)

e) Drum Traps. Drum traps shall be 3 or 4 inches in diameter and provided with a fixed water seal of at least 2 inches. The trap cleanout shall be one size less than the trap diameter.

f) Trap Seal. Each trap shall have a water seal of 2 inches except where a deeper seal is required to prevent the loss of the trap seal by evaporation. Where loss of the trap seal may occur due to evaporation, one of the following shall be used:

1) Vegetable oil may be added to the trap.

2) A deeper seal not to exceed 8 inches may be used.

3) An automatic trap primer may be used.

g) Trap Cleanouts

1) Each fixture trap, except those cast integrally or in combination with fixtures in which the trap seal is readily accessible or except when a portion of the trap is readily removable for cleaning purposes, shall have an accessible threaded or cam lock cleanout plug of ample size protected by the water seal. (Exception: See subsection (g)(4).) The cleanout plug shall be of brass or other non-corrosive type material. (See Appendix D.Illustration D.)

2) Trap cleanouts shall be made gas and water-tight with a threaded cleanout plug and approved washer.

3) A P-trap that is used on a bath waste shall be directly below the tub overflow. The overflow shall be fastened to the tub by means other than the face plate.

4) A P-trap on a plumbing fixture that is not accessible may be installed without a cleanout plug or having a portion of the trap readily removable, provided that there is access to a cleanout within 3 feet of the trap.

h) Trap Level and Protection. Traps shall be set level with respect to their water seals and, where necessary, they shall be protected from freezing.

i) Traps Underground. Underground traps shall be provided with accessible and removable cleanouts, except for separate "P" traps into which floor drains, urinals and other fixtures with removable drain strainers discharge.

j) Building (House) Traps. No trap shall be installed at the base of a soil or waste stack or in a building drain.

k) Prohibited Traps. Use of the following traps is prohibited (see Appendix D.Illustration E):

1) Traps that depend upon the action of movable parts for their seal;

2) Full "S" traps. Exception: Water closet and similar fixtures that depend on self-siphonage for their proper operation;

3) Bell traps;

4) Crown vented traps;

5) Unvented running traps; and

6) Fixtures with concealed interior partitioned traps. Exception: Fixtures with integral traps constructed of vitrified earthenware and penal institutional fixtures with integral traps constructed of ferrous material.

l) Double Trapping. No fixture shall be double trapped.

(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)






b) Minimum Size of Building Drain, Horizontal Branches, Drainage Piping

1) The minimum size of any gravity building drain shall be 4 inches in diameter.

2) Pressure-building drains shall not be used where gravity drains may be installed. Pressure-building drains shall be sized in accordance with the ejector pump manufacturer's recommendation, but shall not be less than 2 inches in diameter.

3) Gravity drained horizontal branches of the building drain shall be sized in accordance with Appendix A.Table H.

4) No portion of the drainage system installed underground or below a basement or cellar shall be less than 2 inches in diameter. The venting system is excluded from this requirement.

5) The drainage piping shall not be reduced in size in the direction of flow.

c) Minimum Size of Soil and Waste Stacks. No soil or waste stack shall be smaller than the largest horizontal branch connected to the stack, except that a 4 inch by 3 inch water closet connection shall not be considered as a reduction in pipe size.

d) Waste Stacks Serving Kitchen Sinks. In one- or two-family dwellings in which the waste stack or vent receives the discharge of a kitchen-type sink and also serves as a vent for fixtures connected to the horizontal portion of the branch served by the waste stack, the minimum size of the waste stack up to the highest sink branch connection shall be 2 inches in diameter. Above that point the size of the stack shall be governed by the total number of drainage fixture units vented by the stack. (See Appendix J.Illustration F.)

e) Future Fixtures. If the future installation of fixtures is provided for during initial construction, the fixtures provided for shall be considered in determining the required size of drain pipes and vent piping. Piping provided for future installation of fixtures shall be terminated with a plugged fitting or fittings at the stack so as to form no dead ends. In a multi-story building, when openings are roughed in for future fixtures below the uppermost level, properly sized vent piping shall be connected to the vent system and carried down to the appropriate lower level and be capped or plugged in an accessible location for venting of the future fixtures.

(Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)


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## wyrickmech (Mar 16, 2013)

leakfree said:


> I've done thousands of tubs under Il. State code and under Chicago code and have never had an inspector make me use a 4" trap on a tub or shower.Sections below are dated 4/14/2014 and don't differ much from earlier versions 7: PUBLIC HEALTH CHAPTER I: DEPARTMENT OF PUBLIC HEALTH SUBCHAPTER r: WATER AND SEWAGE PART 890 ILLINOIS PLUMBING CODE SECTION 890.410 FIXTURE TRAPS/CONTINUOUS WASTE Section 890.410 Fixture Traps/Continuous Waste a) Fixture Traps. All directly connected plumbing fixtures, except those having integral traps, shall be separately trapped by a water-seal trap, placed as close to the fixture outlet as possible. A kitchen sink with up to three basins may be installed on one trap if one compartment is not more than 6 inches deeper than the other and the waste outlets are not more than 30 inches apart. (See Appendix D.Illustration A.) b) Distance of Trap to Fixture. The developed length from the fixture outlet to the trap weir shall not exceed 24 inches, except that an interceptor used as a trap shall be located as close as possible to the fixture. The maximum developed length from the fixture outlet to the inlet of the interceptor shall not exceed 5 feet. (See Appendix D.Illustration B.) The standpipe inlet for an automatic clothes washer shall not exceed 48 inches above the weir of a trap. c) Trap Size. The size of trap for a fixture shall comply with Appendix A.Table E for minimum size of traps. No trap shall be larger than the fixture drain to which it is connected or the drainage pipe into which it discharges. d) Type of Traps. Traps shall have a uniform and smooth interior, and shall have no partitions or movable parts. The trap seal shall be non-adjustable. (See Appendix D.Illustration C.) e) Drum Traps. Drum traps shall be 3 or 4 inches in diameter and provided with a fixed water seal of at least 2 inches. The trap cleanout shall be one size less than the trap diameter. f) Trap Seal. Each trap shall have a water seal of 2 inches except where a deeper seal is required to prevent the loss of the trap seal by evaporation. Where loss of the trap seal may occur due to evaporation, one of the following shall be used: 1) Vegetable oil may be added to the trap. 2) A deeper seal not to exceed 8 inches may be used. 3) An automatic trap primer may be used. g) Trap Cleanouts 1) Each fixture trap, except those cast integrally or in combination with fixtures in which the trap seal is readily accessible or except when a portion of the trap is readily removable for cleaning purposes, shall have an accessible threaded or cam lock cleanout plug of ample size protected by the water seal. (Exception: See subsection (g)(4).) The cleanout plug shall be of brass or other non-corrosive type material. (See Appendix D.Illustration D.) 2) Trap cleanouts shall be made gas and water-tight with a threaded cleanout plug and approved washer. 3)  A P-trap that is used on a bath waste shall be directly below the tub overflow. The overflow shall be fastened to the tub by means other than the face plate. 4) A P-trap on a plumbing fixture that is not accessible may be installed without a cleanout plug or having a portion of the trap readily removable, provided that there is access to a cleanout within 3 feet of the trap. h) Trap Level and Protection. Traps shall be set level with respect to their water seals and, where necessary, they shall be protected from freezing. i) Traps Underground. Underground traps shall be provided with accessible and removable cleanouts, except for separate "P" traps into which floor drains, urinals and other fixtures with removable drain strainers discharge. j) Building (House) Traps. No trap shall be installed at the base of a soil or waste stack or in a building drain. k) Prohibited Traps. Use of the following traps is prohibited (see Appendix D.Illustration E): 1) Traps that depend upon the action of movable parts for their seal; 2) Full "S" traps. Exception: Water closet and similar fixtures that depend on self-siphonage for their proper operation; 3) Bell traps; 4) Crown vented traps; 5) Unvented running traps; and 6) Fixtures with concealed interior partitioned traps. Exception: Fixtures with integral traps constructed of vitrified earthenware and penal institutional fixtures with integral traps constructed of ferrous material. l) Double Trapping. No fixture shall be double trapped. (Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014) b) Minimum Size of Building Drain, Horizontal Branches, Drainage Piping 1) The minimum size of any gravity building drain shall be 4 inches in diameter. 2) Pressure-building drains shall not be used where gravity drains may be installed. Pressure-building drains shall be sized in accordance with the ejector pump manufacturer's recommendation, but shall not be less than 2 inches in diameter. 3) Gravity drained horizontal branches of the building drain shall be sized in accordance with Appendix A.Table H. 4) No portion of the drainage system installed underground or below a basement or cellar shall be less than 2 inches in diameter. The venting system is excluded from this requirement. 5) The drainage piping shall not be reduced in size in the direction of flow. c) Minimum Size of Soil and Waste Stacks. No soil or waste stack shall be smaller than the largest horizontal branch connected to the stack, except that a 4 inch by 3 inch water closet connection shall not be considered as a reduction in pipe size. d) Waste Stacks Serving Kitchen Sinks. In one- or two-family dwellings in which the waste stack or vent receives the discharge of a kitchen-type sink and also serves as a vent for fixtures connected to the horizontal portion of the branch served by the waste stack, the minimum size of the waste stack up to the highest sink branch connection shall be 2 inches in diameter. Above that point the size of the stack shall be governed by the total number of drainage fixture units vented by the stack. (See Appendix J.Illustration F.) e) Future Fixtures. If the future installation of fixtures is provided for during initial construction, the fixtures provided for shall be considered in determining the required size of drain pipes and vent piping. Piping provided for future installation of fixtures shall be terminated with a plugged fitting or fittings at the stack so as to form no dead ends. In a multi-story building, when openings are roughed in for future fixtures below the uppermost level, properly sized vent piping shall be connected to the vent system and carried down to the appropriate lower level and be capped or plugged in an accessible location for venting of the future fixtures. (Source: Amended at 38 Ill. Reg. 9940, effective April 24, 2014)


 b-4 clearly states 2 in is allowed in underground it sounds like a contradiction.


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## leakfree (Apr 3, 2011)

wyrickmech said:


> b-4 clearly states 2 in is allowed in underground it sounds like a contradiction.



The only catch to the code is that every individual village in Illinois is allowed to have amendments to the state code and some prohibit the use of 4" below grade,but i still have never come across an inspector who wanted a 4" trap under a tub in 30+ years.


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## KCplumber (Dec 31, 2009)

I know Illinois has some strange codes but I'm pretty sure RJ was messing with ya


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## 422 plumber (Jul 31, 2008)

I was doing a basement remodel years ago in Cook County, I can't remember what town, and he failed my cast iron underground. I had to replace a 4x2 wye with a 4" wye and p-trap and reduce it on the riser.

Sent from my iPhone using PlumbingZone


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## leakfree (Apr 3, 2011)

422 plumber said:


> I was doing a basement remodel years ago in Cook County, I can't remember what town, and he failed my cast iron underground. I had to replace a 4x2 wye with a 4" wye and p-trap and reduce it on the riser.
> 
> Sent from my iPhone using PlumbingZone


Sounds like a TPI inspection where Steve T******* had a big burr in his a** that day,state inspectors have no problem over ruling them if you want to pick a fight,been there done it.


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## rjbphd (Feb 5, 2010)

leakfree said:


> Sounds like a TPI inspection where Steve T******* had a big burr in his a** that day,state inspectors have no problem over ruling them if you want to pick a fight,been there done it.


Same here.. the same azz won't even show up when I'm there, won't even show his plumber license when asked..


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## leakfree (Apr 3, 2011)

rjbphd said:


> Same here.. the same azz won't even show up when I'm there, won't even show his plumber license when asked..


Steve T has one,I saw it about 10 years ago in Bloomingdale,don't know about the rest of his crew.


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## nhmaster3015 (Aug 5, 2008)

I go to Wally World and buy a Rubbermaid storage bin, the heavy duty kind. Turn it upside down where the drain will be and let it stick above the pour. Sawzall it at the floor level when ready to proceed.


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## Bayside500 (May 16, 2009)

nhmaster3015 said:


> I go to Wally World and buy a Rubbermaid storage bin, the heavy duty kind. Turn it upside down where the drain will be and let it stick above the pour. Sawzall it at the floor level when ready to proceed.


we install the trap on rough in and stub up a piece of 1 1/2" for drain

we use these ............
http://www.oatey.com/products/rough-in-products/tub-box/tub-box

drill a hole in the bottom one for the drain riser. 

we put 2 together and fill the bottom one with dirt to keep it from floating in wet concrete.

the corners have pre-punched holes we knock out and ziptie the 2 boxes together


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## Michaelcookplum (May 1, 2011)

Trap should be in ground with 2" stubbed up. If you can read a set of plans and know how to use a tape measure, when it comes time to set the tub at the most you might be a 22 or 45 off. I use styrofoam blocks left in site by concrete guys to box out for shoe. AFR tubs are nice for basements. No need to box out anything


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## Michaelcookplum (May 1, 2011)

Here's a pic of what I like to do


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## Michaelcookplum (May 1, 2011)

Another pic


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