kmuddzy
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Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County
I am a DYI’er and I’m excited to do my first house plumbing rough-in for a house remodel and new addition. I tried to answer as many questions as I could by researching the web but I need to get a few answers I couldn’t find as well as confirm some answers I found. I apologize for the number of questions but I didn’t want to post 10 different threads. I would pay a qualified plumber an hourly rate to check in on me while I'm doing this but I haven't found that person, either. Thanks in advance for your help!!!
First, horizontal or horizontally means that there is at least a ¼” slope.
1. Can I run a 1-½” vanity drain horizontal along a 2x4 wall and around a 90deg corner? i.e. can I use a 90deg fitting to turn the corner?
2. After the shower’s p-trap, I am showing a 2” drain running to a ‘T’ and the top of the ‘T’ is a 1.5” vent. Can a 1.5” vanity drain ‘T’ to this 1.5” vent pipe for drainage purposes (creating about a 4’ section of vertical wet vent for the shower)? If I do this should the “wet vent” section be 2 inches?
3. How far can a vanity 1 ½” sink drain run horizontal along a wall before it turns down to run to 3” sewer pipe?
4. I have a 3” toilet drain that runs 5’ horizontally to a “T”. Can the top of the “T” be 1.5” for the vent?
5. What is the largest diameter pipe that can go through double 2x6” top plate on a structural wall?
6. Am I correct that the minimum slope on a 2 inch or less pipe is ¼” per ft, 3” or larger is 1/8” per ft and on all pipe the maximum slope is ½” per ft ?
7. Am I correct that if a horizontal run has to be greater than ½” per foot then a 45 degree drop should be used and there is no minimum or maximum length to this 45 degree drop before it returns to the horizontal pipe slope?
8. If I have a 1 ½” kitchen sink vent pipe extending vertically to the 2nd floor and then running horizontal for 20’ before going vertical through the attic to the roof. During the 20’ horizontal length I will have the 1 ½” vents for a washer, 2 vanities, a shower and a tub connecting to it. Should this vent pipe be increased to 2” somewhere along the way or can 1 ½” run to the roof?
9. Am I correct that all drain pipes are a min. 1.5” except for a shower (2”) and a toilet (3”)?
10. What’s the minimum size joist one can use below a shower if the p-trap is as tight to the drain as it can be? I.e. will a 2” shower p-trap fit within the 7” of a 2x8 joist bay below it (old house joists)?
11. If I’m correct, one can drill a hole in a joist as long as the diameter is no more than 1/4 the height and the hole is not located in the middle 1/3rd of the length. Therefore I cannot drill a 2” hole in my 2x8 joists. BUT, am I allowed to cut the joist entirely, install a double 2x8 header to the 2 adjacent joists (joists will NOT be sistered)?
12. Is there a min and maximum distance from a Tub or shower drain to the p-trap below it? I have 2x12 floor I-joists and then some space below those where I would like to locate the p-trap before the drains run horizontal.
13. Can a 3” Radon pipe travel horizontally (90deg bend) for 5’ before going vertical again (another 90deg bend)?
14. Does the top elevation of a 3” radon pipe have to be within a certain distance from the elevation of the peak of the roof? My 1 radon pipe can exit straight up to the roof but it will exit within 2’ of the gutters. The only option I have is to run it up along the rafters and then exit the roof higher up.
15. The existing house had a kitchen, 1 full bath and laundry – all draining down to a 3” PVC pipe running to the septic. Now we are adding 2 full bathrooms. Will the 3” PVC pipe be adequate?
I hope the above is clear. Thanks for your help!!!!
Keith
Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County
I am a DYI’er and I’m excited to do my first house plumbing rough-in for a house remodel and new addition. I tried to answer as many questions as I could by researching the web but I need to get a few answers I couldn’t find as well as confirm some answers I found. I apologize for the number of questions but I didn’t want to post 10 different threads. I would pay a qualified plumber an hourly rate to check in on me while I'm doing this but I haven't found that person, either. Thanks in advance for your help!!!
First, horizontal or horizontally means that there is at least a ¼” slope.
1. Can I run a 1-½” vanity drain horizontal along a 2x4 wall and around a 90deg corner? i.e. can I use a 90deg fitting to turn the corner?
2. After the shower’s p-trap, I am showing a 2” drain running to a ‘T’ and the top of the ‘T’ is a 1.5” vent. Can a 1.5” vanity drain ‘T’ to this 1.5” vent pipe for drainage purposes (creating about a 4’ section of vertical wet vent for the shower)? If I do this should the “wet vent” section be 2 inches?
3. How far can a vanity 1 ½” sink drain run horizontal along a wall before it turns down to run to 3” sewer pipe?
4. I have a 3” toilet drain that runs 5’ horizontally to a “T”. Can the top of the “T” be 1.5” for the vent?
5. What is the largest diameter pipe that can go through double 2x6” top plate on a structural wall?
6. Am I correct that the minimum slope on a 2 inch or less pipe is ¼” per ft, 3” or larger is 1/8” per ft and on all pipe the maximum slope is ½” per ft ?
7. Am I correct that if a horizontal run has to be greater than ½” per foot then a 45 degree drop should be used and there is no minimum or maximum length to this 45 degree drop before it returns to the horizontal pipe slope?
8. If I have a 1 ½” kitchen sink vent pipe extending vertically to the 2nd floor and then running horizontal for 20’ before going vertical through the attic to the roof. During the 20’ horizontal length I will have the 1 ½” vents for a washer, 2 vanities, a shower and a tub connecting to it. Should this vent pipe be increased to 2” somewhere along the way or can 1 ½” run to the roof?
9. Am I correct that all drain pipes are a min. 1.5” except for a shower (2”) and a toilet (3”)?
10. What’s the minimum size joist one can use below a shower if the p-trap is as tight to the drain as it can be? I.e. will a 2” shower p-trap fit within the 7” of a 2x8 joist bay below it (old house joists)?
11. If I’m correct, one can drill a hole in a joist as long as the diameter is no more than 1/4 the height and the hole is not located in the middle 1/3rd of the length. Therefore I cannot drill a 2” hole in my 2x8 joists. BUT, am I allowed to cut the joist entirely, install a double 2x8 header to the 2 adjacent joists (joists will NOT be sistered)?
12. Is there a min and maximum distance from a Tub or shower drain to the p-trap below it? I have 2x12 floor I-joists and then some space below those where I would like to locate the p-trap before the drains run horizontal.
13. Can a 3” Radon pipe travel horizontally (90deg bend) for 5’ before going vertical again (another 90deg bend)?
14. Does the top elevation of a 3” radon pipe have to be within a certain distance from the elevation of the peak of the roof? My 1 radon pipe can exit straight up to the roof but it will exit within 2’ of the gutters. The only option I have is to run it up along the rafters and then exit the roof higher up.
15. The existing house had a kitchen, 1 full bath and laundry – all draining down to a 3” PVC pipe running to the septic. Now we are adding 2 full bathrooms. Will the 3” PVC pipe be adequate?
I hope the above is clear. Thanks for your help!!!!
Keith
Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County
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