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New Garage - floor drain?


Mocephus

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Hi friends, I’m in the process of building a 26 x60 garage for my ‘05 Signature. I will have water and electric to the building but not sewer (not practical where I’m building).

I’m debating on whether or not to install a floor drain(s) and would like to hear what others have done. Thanks in advance!

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We keep our Dynasty in a 66’ x 50’ hangar portion of our shop. Instead of floor drains we simply put a slight slope on the floor. I’m thinking it was maybe 2” in fifty feet. Hangar door is 50’ x 16’. There’s  a 50’ apron outside with the same slope. Everything washes out pretty well. Occasionally need a squeegee where the contractor shorted a little concrete and caused a slight puddle. Have full hookups inside and out.

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When I built my RV garage/shop back in 2007, I was going to put a floor drain in.  But when it went through the city plan check process, I had to add an oil separator outside and show them proof I had a contract with a licensed vacuum truck to service the tank on a regular basis..  They were treating the building like it was going to be a mechanic's workshop with spilled oil/diesel going down the drain.   Needless to say, I removed the drain from my plans.

Edited by windsorbill06
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Like windsorbill06, my construction code authority treated a drain over the top.   I ended up with a drain on both sides of the barn, but don't tell anyone...   So gently ask the permit office on what the rules are for your area.

I did make a mistake of putting too much fall to the drains.  At some point, I will float a layer of concrete above to flatten it.  Just have been worried about the top layer breaking away from the bottom...so do it right when the cement is wet!

Edited by DavidL
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I am in the process of building a 40X50' garage.  I have the concrete pad poured and waiting on the building.  16' of it is for the motor home and 24' for parking and I am building a 24X28' workshop within the building and have storage above it.    I put power and water into the garage and will complete the wiring sometime in the future. 

I put in a sewer hookup with a floor drain close to it in case I have any "spillage" while dumping tanks.  I also positioned this close to where the front drivers side wheel will be an if I run the AC the condensate will drain into it.    This is plumbed into my home septic.  https://www.lowes.com/pd/Oatey-L-Bell-Trap-Drain/50315073

I also put a floor drain centered below the engine area to catch any condensate.  I actually used a 5' section of pool drain to provide for a larger area to slope to.  https://www.lowes.com/pd/NDS-5-ft-L-x-1-1-4-in-W-x-1-in-dia-Channel-Drain-Kit/3514344

We get heavy winds & rain from the west which is the side of the building that I have a 14' & 9' garage door located on.  I was concerned about rain blowing in under the door so I put a 3' floor drain centered in the door opening ~3 into the building.  https://www.ebay.com/itm/TUF-TITE-TPAN-36-Trench-Pan-Drain-36-inches-long/141796041527?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

I live in E TN and the building permit requirements aren't that stringent.  I had to show approximate location of building on the lot in relation to house and septic.  I provided a brochure from the company I am purchasing the building and a sales contract.  When the inspector looked at the site prior to concrete pour he looked at the drains and took some pictures of the site and that was it. 

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1 hour ago, DavidL said:

Like windsorbill06, my construction code authority treated a drain over the top.   I ended up with a drain on both sides of the barn, but don't tell anyone...   So gently ask the permit office on what the rules are for your area.

I did make a mistake of putting too much fall to the drains.  At some point, I will float a layer of concrete above to flatten it.  Just have been worried about the top layer breaking away from the bottom...so do it right when the cement is wet!

Good insight. Thanks David!

 

1 hour ago, windsorbill06 said:

When I built my RV garage/shop back in 2007, I was going to put a floor drain in.  But when it went through the city plan check process, I had to add an oil separator outside and show them proof I had a contract with a licensed vacuum truck to service the tank on a regular basis..  They were treating the building like it was going to be a mechanic's workshop with spilled oil/diesel going down the drain.   Needless to say, I removed the drain from my plans.

Thanks Bill. I was told by permitting

 

2 hours ago, Xlr8ting1 said:

We keep our Dynasty in a 66’ x 50’ hangar portion of our shop. Instead of floor drains we simply put a slight slope on the floor. I’m thinking it was maybe 2” in fifty feet. Hangar door is 50’ x 16’. There’s  a 50’ apron outside with the same slope. Everything washes out pretty well. Occasionally need a squeegee where the contractor shorted a little concrete and caused a slight puddle. Have full hookups inside and out.

 

2 hours ago, Xlr8ting1 said:

We keep our Dynasty in a 66’ x 50’ hangar portion of our shop. Instead of floor drains we simply put a slight slope on the floor. I’m thinking it was maybe 2” in fifty feet. Hangar door is 50’ x 16’. There’s  a 50’ apron outside with the same slope. Everything washes out pretty well. Occasionally need a squeegee where the contractor shorted a little concrete and caused a slight puddle. Have full hookups inside and out.

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I have septic for the shop sink, office and bathroom part of the shop but never needed any floor drains. I just don't spill a lot of stuff on the floor and if I did, I would not want it in the septic anyway. Never even crossed my mind when it was built and never needed it.

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2 minutes ago, Ivan K said:

I have septic for the shop sink, office and bathroom part of the shop but never needed any floor drains. I just don't spill a lot of stuff on the floor and if I did, I would not want it in the septic anyway. Never even crossed my mind when it was built and never needed it.

Thanks Ivan!

4 minutes ago, Mocephus said:

Good insight. Thanks David!

 

Thanks Bill. I was told by permitting that I could put a floor drain in that drained outside since it was just for washing the coach. A plumber,however, told me that he was required to put in an outdoors oil separator, by the same permitting office, on a similar job. I guess I’ll find out for sure on inspection day!

 

 

8 minutes ago, Mocephus said:

Good insight. Thanks David!

 

Thanks Bill. I was told by permitting

 

 

Thanks Theo!

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Moe,

It has a lot to do with your jurisdiction.  Mine didn't even get through plan check.  You might be fine, or maybe the inspector will call you on it.   I ended up putting a flat smooth floor, no slope.  It's easy to roll around under the coach with a creeper,  and I just pull coach out a few times a year and give it a good wash down.  Even if I had floor drains, I would not be washing inside.

I've always dreamed of a pit, but that's another story.

What ever you end up doing, I'd seal the concrete.  I ended up doing an epoxy finish.  

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I do wish I had floor drains where the A/C drains are, I have a system of pvc pipe I can put in place if I need to run the A/C while it’s in the shop.    
 

The biggest thing I wish I had in the shop would be a pit under the motorhome.   It could just be in the back and not too deep.   It wouldn’t add much to the cost, just a little extra forming and rebar. ( if you aren’t dealing with regulations and inspectors )

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Not sure this would matter to most, especially if you don't work on your own coach, but when I built our garage I made sure the floor was level. I even purchased a laser level and drew a line around the cinder block foundation wall for the concrete guy to follow. My reasoning was I wanted a level place to adjust the ride height. Before building the garage I had to pull down into the cul-de-sac to adjust the ride height. I was my own contractor and the sub I hired to pour the floor tried to talk me into a floor that sloped toward the garage doors but I refused. I have the driveway poured lower than the garage floor so there is a lip to keep the rain out and the driveway slopes down hill away from the doors. There is no water in the garage except for what is in the coach. I guess if the coach springs a leak I will have to sweep the water out. My garage, my choice. A floor drain would have to run all the way out to the street which would require digging up the curb. I don't think the county would approve that and to reach one of the street drains would require digging up the neighbor's yard. Over three years now with many heavy rains and no problems. We don't run the air conditioners inside the garage because the garage has its own HVAC system and stays at 74 in the summer and 64 in the winter.

 

Edited by Bob Nodine
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12 hours ago, windsorbill06 said:

Moe,

It has a lot to do with your jurisdiction.  Mine didn't even get through plan check.  You might be fine, or maybe the inspector will call you on it.   I ended up putting a flat smooth floor, no slope.  It's easy to roll around under the coach with a creeper,  and I just pull coach out a few times a year and give it a good wash down.  Even if I had floor drains, I would not be washing inside.

I've always dreamed of a pit, but that's another story.

What ever you end up doing, I'd seal the concrete.  I ended up doing an epoxy finish.  

Yes, I will definitely seal the floor. Thanks!

4 hours ago, Bob Nodine said:

Not sure this would matter to most, especially if you don't work on your own coach, but when I built our garage I made sure the floor was level. I even purchased a laser level and drew a line around the cinder block foundation wall for the concrete guy to follow. My reasoning was I wanted a level place to adjust the ride height. Before building the garage I had to pull down into the cul-de-sac to adjust the ride height. I was my own contractor and the sub I hired to pour the floor tried to talk me into a floor that sloped toward the garage doors but I refused. I have the driveway poured lower than the garage floor so there is a lip to keep the rain out and the driveway slopes down hill away from the doors. There is no water in the garage except for what is in the coach. I guess if the coach springs a leak I will have to sweep the water out. My garage, my choice. A floor drain would have to run all the way out to the street which would require digging up the curb. I don't think the county would approve that and to reach one of the street drains would require digging up the neighbor's yard. Over three years now with many heavy rains and no problems. We don't run the air conditioners inside the garage because the garage has its own HVAC system and stays at 74 in the summer and 64 in the winter.

 

Thanks Bob! I like your attention to detail! It sounds like you did a great job on your garage. Anything that you would do differently?

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12 hours ago, granvillebarker said:

I do wish I had floor drains where the A/C drains are, I have a system of pvc pipe I can put in place if I need to run the A/C while it’s in the shop.    
 

The biggest thing I wish I had in the shop would be a pit under the motorhome.   It could just be in the back and not too deep.   It wouldn’t add much to the cost, just a little extra forming and rebar. ( if you aren’t dealing with regulations and inspectors )

Thanks Granville! I won’t have heat or air in the building so running the ac when working inside the coach in the summer will be a must. Thanks for highlighting the ac draining issue.

A pit would be nice for sure!

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On my dynasty, the front a/c drains at the front by the generator on the drivers side, the mid a/c near the tank bay on the pass side, and the rear A/C at the very back drivers side.    So you may want a few strategically located drains.  I’d put one under the water tank and aquahot drains as well if I were doing it.

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14 hours ago, jacwjames said:

I am in the process of building a 40X50' garage.  I have the concrete pad poured and waiting on the building.  16' of it is for the motor home and 24' for parking and I am building a 24X28' workshop within the building and have storage above it.    I put power and water into the garage and will complete the wiring sometime in the future. 

I put in a sewer hookup with a floor drain close to it in case I have any "spillage" while dumping tanks.  I also positioned this close to where the front drivers side wheel will be an if I run the AC the condensate will drain into it.    This is plumbed into my home septic.  https://www.lowes.com/pd/Oatey-L-Bell-Trap-Drain/50315073

I also put a floor drain centered below the engine area to catch any condensate.  I actually used a 5' section of pool drain to provide for a larger area to slope to.  https://www.lowes.com/pd/NDS-5-ft-L-x-1-1-4-in-W-x-1-in-dia-Channel-Drain-Kit/3514344

We get heavy winds & rain from the west which is the side of the building that I have a 14' & 9' garage door located on.  I was concerned about rain blowing in under the door so I put a 3' floor drain centered in the door opening ~3 into the building.  https://www.ebay.com/itm/TUF-TITE-TPAN-36-Trench-Pan-Drain-36-inches-long/141796041527?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

I live in E TN and the building permit requirements aren't that stringent.  I had to show approximate location of building on the lot in relation to house and septic.  I provided a brochure from the company I am purchasing the building and a sales contract.  When the inspector looked at the site prior to concrete pour he looked at the drains and took some pictures of the site and that was it. 

Jim, thanks for the details and links to the drains. Great planning on your part! Your response was very helpful!

2 minutes ago, granvillebarker said:

On my dynasty, the front a/c drains at the front by the generator on the drivers side, the mid a/c near the tank bay on the pass side, and the rear A/C at the very back drivers side.    So you may want a few strategically located drains.  I’d put one under the water tank and aquahot drains as well if I were doing it.

Yep, I’m really thinking hard about a series of channel drains down the center of the garage. That should take care of the AC drainage, AquaHot, etc. 

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There has been a fairly extensive thread on IRV2 on building a garage.  I took some of the ideas from there. 

When I formed up for the concrete pad the building supplier spec'd a monolithic pour around the perimeter of the building, which was a 1'X1' trench below the concrete with rebar for reinforcement, it called for 2 runs of rebar, I did 3. 

I also poured the 16' wide section where the RV will park an average of 8" thick and also used rebar on ~8" centers where the tires run and across the front and back where the tires and jacks are located.  After the concrete was poured I kept it wet down ~8 times a day for over a week.  Wet curing concrete increases it's strength by ~50%. 

The pad required ~55 yards of concrete as I also had a 12'X33' parking area on one side.  Concrete was $145/yd and finishing was $1.25 per sqft. 

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  Great subject and great posts Jim & et al.   

  Concrete comes in different PSI ratings / mixes I think 3000 psi is about standard around here but what did you use ?                                Did you do any cutting/sawing in case the concrete decides to crack ?

 Concrete contractors get a little vague when you press them on the mix they plan to use .    When / if I build mine I hope to buy the   cement myself if I can .     In the past I recall seeing concrete being covered with very large tarps to help the curing but I don't believe I   see that anymore around here in E Tx .  I suppose they use additives to help in that regard .

   Ray

Edited by Ray Davis
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I used 4000 psi concrete. 

Yes, the finishers did cut the concrete.   I had them do one cut at the 16' mark where the concrete changed thickness and then they did 3 cuts front to back.  So far I have no cracks.  I waited for over 2 weeks before moving my motorhome onto the slab.   With this large of slab I'll be surprised if I don't get a crack or two. 

Prepping a site is important.  The soil base that I have, once I excavated the area to grade, was clay and very competent.  Prior to pouring concrete one of my wives friends visited with a 40' Thor outlaw and she used the jacks to level.  After she left 3 of the jacks did not sink and one did about 1 inch.  

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1 hour ago, jacwjames said:

I used 4000 psi concrete. 

Yes, the finishers did cut the concrete.   I had them do one cut at the 16' mark where the concrete changed thickness and then they did 3 cuts front to back.  So far I have no cracks.  I waited for over 2 weeks before moving my motorhome onto the slab.   With this large of slab I'll be surprised if I don't get a crack or two. 

Prepping a site is important.  The soil base that I have, once I excavated the area to grade, was clay and very competent.  Prior to pouring concrete one of my wives friends visited with a 40' Thor outlaw and she used the jacks to level.  After she left 3 of the jacks did not sink and one did about 1 inch.  

Wow that sounds like it was great soil. My spot has been graded and cut down to red clay. I’m having 4” of stone under the slab. I’m going with 4000 psi concrete, 6” deep, 12” footers and #4 rebar 16” oc. He’ll cut expansion joints as well. 

1 hour ago, jacwjames said:

There has been a fairly extensive thread on IRV2 on building a garage.  I took some of the ideas from there. 

When I formed up for the concrete pad the building supplier spec'd a monolithic pour around the perimeter of the building, which was a 1'X1' trench below the concrete with rebar for reinforcement, it called for 2 runs of rebar, I did 3. 

I also poured the 16' wide section where the RV will park an average of 8" thick and also used rebar on ~8" centers where the tires run and across the front and back where the tires and jacks are located.  After the concrete was poured I kept it wet down ~8 times a day for over a week.  Wet curing concrete increases it's strength by ~50%. 

The pad required ~55 yards of concrete as I also had a 12'X33' parking area on one side.  Concrete was $145/yd and finishing was $1.25 per sqft. 

That’s a great idea about adding more rebar along the tracks of where the rv will go. I’ll add that to my plan.  My building manufacturer calls for the same footing and rebar requirements. 

1 hour ago, Ray Davis said:

  Great subject and great posts Jim & et al.   

  Concrete comes in different PSI ratings / mixes I think 3000 psi is about standard around here but what did you use ?                                Did you do any cutting/sawing in case the concrete decides to crack ?

 Concrete contractors get a little vague when you press them on the mix they plan to use .    When / if I build mine I hope to buy the   cement myself if I can .     In the past I recall seeing concrete being covered with very large tarps to help the curing but I don't believe I   see that anymore around here in E Tx .  I suppose they use additives to help in that regard .

   Ray

Hi Ray, mine hasn’t been poured yet but I’m going with 4” of stone under the slab, 4000 psi concrete, 6” deep, 12” footers and #4 rebar 16” oc.

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One thing I did and really liked, but it seems trivial, was to do a saw cut from the middle of the door opening straight back to the back of the garage.  I back my coach in, so I can see the saw cut in the back up monitor.  I line up the trailer hitch (or tow bar) with that line, and coach is centered perfectly inside the door opening and makes lining up/ backing in a breeze.

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1 hour ago, windsorbill06 said:

One thing I did and really liked, but it seems trivial, was to do a saw cut from the middle of the door opening straight back to the back of the garage.  I back my coach in, so I can see the saw cut in the back up monitor.  I line up the trailer hitch (or tow bar) with that line, and coach is centered perfectly inside the door opening and makes lining up/ backing in a breeze.

Good idea! I may have channel drains to line me up too. 

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20 hours ago, Mocephus said:

Yes, I will definitely seal the floor. Thanks!

Thanks Bob! I like your attention to detail! It sounds like you did a great job on your garage. Anything that you would do differently?

Yes, I would make it wider. We have a small house in a subdivision and the garage is not suppose to be more than 2/3 of the square footage of the house. I stayed within that limit but friends tell me if I had made it 2 feet wider no one would say anything. We have a 12 x 14 door for the RV and a 8 x 8 door for other vehicles. Wish that smaller door was a 9 x 9. That is my big regret that I did not add at least another foot to the width of the garage and make that door 9 x 9.  

Besides using both wire and 4000 psi concrete and pouring it 8 inches thick, at the front of the garage where the 12 x 14 door is I poured the concrete down to the footer. This was because I had the floor higher than the driveway to prevent water intrusion and was worried the heavy coach would crack the floor as it rolled over the edge of the floor.

Also had both the floor and the driveway sawed so the concrete would stress crack along the saw joints.

Edited by Bob Nodine
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Instead of a subterranean drain, you could pour the slab with a curb to direct water away from the walls into a trough in the center of the parking space.  By a trough I mean just an area1-2 inches lower than the sides at the curb.  Slant the trough from the far end toward the overhead door and out the building, or if you will have two doors maybe from the center.  Be specific in your requirements with the concrete company so you get no low spots that will collect liquids.  Require laser leveling to avoid low spots as was mentioned.

Finally, if you think about it you probably want the surface broom swept so you don't have a slip and fall accident.  I know because our concrete was smooth finished and it is very slippery when wet!

If you seal the walls properly or use metal siding you could have a wash bay with proper drainage.  And as Bill said, be sure to seal the floor before you use it.  Product recommended: 

Siloxa-Tek 8505 Ultra Concentrate - 1 Gallon (Makes 5 GALLONS) Penetrating Concrete Sealer, Water, Salt & Oil Repellent  This is a 40% formula, so compare it to others that are 20% or even less (as low as 8%).

In warmer climates any water based siliconate mixture will suffice.  Be sure to match the treatment to the finish on the surface you choose.  There are both smooth finish and rough finish formulations.

 

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I had a limited footprint to work with to gain enough space to build.  Originally I was going to build a 45' long garage but decided to make it 50', and then went from 36 to 40' wide.  This, however, cost me quite a bit of time and money as I had to bring in a large excavator with a rock breaker to get rid of a large outcropping of rock in the SE corner and even still didn't get as much as I wanted.   Had to build a retaining wall on 2 sides.  

The approach to the garage is at a slight angle so I decided to go with a 14' X 14' garage door for the motorhome and originally I spec'd a 8'X 8' garaage door but changed to 9' wide, glad I did.    So if you have limitations for access I'd suggest finding a parking lot, laying out the garage and access and practice parking the coach to confirm it's possible. 

Since the garage is not built yet I took a day and practiced parking the motorhome.  My wife said that if she parked the motorhome she would pull it in going forward, which I told here probably wouldn't work due to having to come in at an angle.  I was right, pulling it in was OK but backing it out was a bear since there is a fence that I had to deal with.  Backing it in was pretty easy since you hug the side of the door and swing the front around once the back wheels are at the door.  Placement of the sewer and floor drain gives a good target for the rear wheels and the long floor drain also helps.  I'm sure once the garage itself is in place it will be a bit more difficult but not too bad.  

If you don't want to go through the wet curing process you can specify that your concrete guys seal the floor right after is finished, this helps retain the moisture and slows the cure.   I also put down 6 mil plastic for a vapor barrier but this also helps retain moisture.  The longer the cure time the stronger the concrete.  Ideally it would have been better if I kept wetting the concrete for 30 days but the first 7 days is the most important and you gain about 80% of the strength in the that time.  

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A tight building code enforced area makes projects tougher and more expensive. I did a garage floor pour in Michigan once where the inspector told me flat out I couldn't have floor drains. After he left I ran them anyways, taped off the top of them and did the pour. After the final inspection I took a hammer and chipped the thin layer of cement off the top of the drains, removed the tape and finished them. 🙂 

I put in an outdoor poured RV pad at our current house. I am one of those guys when I build something I build it to last. The approach and the first 10 ft of the pad was heavily rebarred and I poured it 8 inches thick. The footer at the lip of the approached I extended 3 ft in at 12 inches deep. If your approach has a slight slant it will be taking a heavy force as the coach pushes onto it and rolls up to the level area of the pad. Cracks or breakage typically happen on the approach as a heavy vehicle transitions onto a level surface. The entire pour was done with 5,000 psi concrete and with fiber mix at 6 inches deep. Pay the extra few dollars and have the fiber added. My pad which I engineered myself is able to bear 80,000 psi.

If I am going to build something I make sure I never skimp on materials. In the end the cost differential is minimal and cutting corners to save money on any building project will com e back to haunt you. That is why I went with 5,000 psi / fiber mixed concrete and added more rebar then I needed and extended the footer at the approach. My concrete guy I hired to do the pour took a look and shook his head and asked, what the hell do you plan on parking here a 747 ?

RV Pad Before.JPG

RV Pad.JPG

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