What is the steepest grade / slope that a home can be backed up on to be installed on a lot?

I have 1.5 acres of vacant land within my park that I would like to develop nine additional lots on.  I will need to bring in fill to build up the land.  When I presented my plans to the county P&Z committee they cited a need to build it up higher to adhere to their newly adopted storm drainage design requirements.  My engineer ran the numbers and I’m concerned that if we do build it that high, we may not be able to install a home because of the steep slope of the approach to the lot.  I’m afraid of either the rear of the home becoming grounded before the wheels reach the incline, rolling the home or twisting the frame.Does anyone have any information on what the steepest grade or slope can be to properly and safely install a 16 x 80 onto a lot?  I would like to make sure my engineer’s plans do not exceed that degree of slope.  If it does, then I would like to use this information to apply for a variance with the board.  

I don’t know the answer, but I know that you also need to be worried about how high the home sits off the ground, as most states have a maximum height above ground level (measured from ground to the bottom of the frame).

The answer to this question seems to be geometry and research.(1) Find out the minimum height a home is allowed to be off the ground per state regulation.  It might be 0" but whatever it is, consider this the minimum “skirting length.”  At the other end is the maximum height, which in Texas I believe is 48" (or greater if installed according to the plans of a licensed engineer.)(2) The home has to sit level.(3) The wheels come off, and for that matter the axle probably comes off, so your slope is probably determined by the rise/run of the “skirting length” min to max.(4) An engineer can override the state installation code if done according to the local municipality’s code.update: (5) Access obviously has to be good enough for the thing can be maneuvered into place.  But if drainage is the real sticking point, I think you could put in a storm sewer or equivalent and get away with less slope  It’s just a hole and a pipe and/or a channel and routing to existing storm drain.  Check out how your local public parks (the green kind) or city public works deal with the problem of high drainage requirements.  That would be my next step.

The height of the home, aside from local codes, should be determined by the park owner based on accessibility to the point where the water and septic come above ground under the home. As the owner of the park you need to make sure you have reasonably easy access to this point.You may also consider a shorter home. A 16’ X 60’-68’ two bed. The smaller home will appeal to fewer applicants but will attract higher quality tenants. Primarily older applicants without kids. I know most park owners are only concerned with filling their park quickly but it never hurts to consider a long term plan of overall upgrading of your community.

Thank you Frank, Brandon and Greg for your replies.  But, I think I may have not properly phrased my question.My question does not pertain to how high a home can or should be blocked up.  My question relates to the slope going from the road to the pad.The county wants me to build up the property with dirt.  So much dirt, that the newly developed area will be higher than my park’s road, possibly as much as 2.5’ to 3’ higher.  It could end up looking like a small plateau.  My concern is in doing so, will the grade be so extreme that it will either be impossible or unsafe to back a home onto the slope to get to the pad.  If the degree of incline is too steep, the home’s rear could hit before the home ever begins to rise.  Or, if installing the home diagonally, the home’s frame could twist, or the home could possibly flip over.Does anyone know what the most extreme slope you can have and still safely back a home over it to get to the pad?

Call a mover & ask & let us know!

You could always build a temporary ramp with timbers and plywood to lessen the slope.  Another approach would be to build a longer approach with dirt or gravel then remove it after the home is in place. You can push them up a pretty good slope but be careful you don’t bend the hitch while pushing it into place.

You mentioned that you are working with an engineer already.  My advice would be to speak with the manufacturer or do some actual measurements in field.  Ideally, you would get the distance of the towing vehicle to the centerline of the hitch on the vehicle, then the centerline of the hitch (ball) to the first axle centerline, the distance of the first axle centerline to the centerline of the last axle.  Finally, the distance of the centerline of the last axle to the rear most point of the frame.  One last measurement would be the height of the bottom of the frame rail above grade while it sits on the wheels on level ground.Your engineer (I’m not one) should be able to take those dimensions and match them up against a vertical profile of the proposed road in order to determine where there might be conflicts.  What you are trying to figure out is not all that different than calculations done on highways for intersections with other roads, railroad crossings, or other grade transitions.  Providing the engineer with the above dimensions should be helpful in determining if the road is possible.  It will also give you great information to provide to the locality should you need a variance!