Lot Drainage Type A

lot drainage type a

yard drainage

Yard Drainage

Importance of Adequate Yard Drainage

Adequate yard drainage in your new home is something that you want to take particular attention to throughout the construction phase of your home. The last thing you want after you have completed your home, is to deal with the hassle of flooding yards as a result of poor drainage in your yard. Creating mud pits, harvesting mosquitos, killing grass, sound like what you want after you move into your beautiful home? I do not thing so.

In the first image of this article, you can get a good idea of how a typical yard should drain.

Drainage swale - A drainage swale is a shaped and sloped depression in the soil surface used to convey water run-off to a desired location

drainage for yard

yard drainage how to

example of yard drainage

Example of Poor Yard Drainage

When building your own home, you will want to perform the tractor rough grade immediately after the slab is poured and the form boards are removed. The purpose of the lot scrape is to provide adequate drainage of surface water away from the slab (Make sure the sewer and water tap have already been completed) The general standards for drainage is set by the Residential Code for One & Two Family Dwellings and the Federal Housing Administration (FHA). Proper lot drainage established now will prevent delays when the final grade is performed later in the process of building your own home.

When you schedule this work during your homes construction, ensure that enough sand is delivered to allow for the job to be completed. At this stage, all swales are cut, the grade is leveled and sloped uniformly over the entire lot. Dirt is leveled to the top of all flat work (if applicable), so the lot drains without holding water. Check slope of swales using a grading tool before the tractor man leaves the job site. After the rough grade is complete, have silt control installed to prohibit erosion from entering the street and sandbags placed on the up slope side of affected storm drains.

Building Your Own Home

Checklist for Tractor Rough Grade

• Before the rough grade, inspect lot condition for prior damage at all flatwork, slab corners, water meter boxes, t-poles, and sewer cleanout(s).
• Swales cut around house & between lots
  • 2% swale gradient (Note: May be reduced to 1% if house will have full gutter installation discharging 3 feet from the slab)
  • Must fall away from front, rear & sides of exposed slab to a minimum of 6 inches within the first 10 feet. Confirm swale depth and placement by using a grading tool (If property line is less than 10 feet, still comply with the 6″ rule)
  • Bottom of swale a minimum of 14 inches above finished slab height (FSH) at rear of slab
• Grade is even and smooth, having no low spots to hold water
• Ensure grade at patio slopes away from top of concrete surface toward swale (if applicable)
• Curb clean accomplished prior to tractor man completing job
• After the rough grade, re-inspect the lot for tractor damage at all flatwork, slab corners, water meter boxes, t-poles, and sewer cleanouts.
• Install silt fencing, or other approved methods (check with city ordinances)

See related posts on lot drainage details, Lot Grading Type A, Lot Grading Type B, and Lot Grading Type C

Construction Notes for Sidewalks & Driveways on Curbed-Type Streets (Residential Areas)

• Proposed driveway, sidewalk, curb, gutter line and grade shall match existing street
• Proposed sidewalk shall be constructed with portland cement (4 1/2″ sack cement per cubic yard). Four inches thick and 4 feet minimum width
• Proposed driveway shall be built with portland cement concrete (4 1/2 sack cement per cubic yard). Six inches thick from proposed saw cut at existing pavement to right-of-way line (front property line) and to be reinforced with 3/8″ inch zero-deformed reinforcing bars (minimum ASTM A615, grade 60, unless noted) spaced at 24-inches center-to-center each way with 6 inches minimum overlap (12″ x 12″ x w4 x w4, or 6″ x 6″ x w6 x w6 – as alternate).
• Proposed driveway reinforcing steel is to be tied to existing roadway reinforcing steel with a minimum overlap of 6 inches.
• Proposed curb and gutter line shall be built with portland cement concrete (4 1/2 sack cement per cubic yard)
• Proposed gutter line is to be maintained at face of existing curb
• Saw cut existing curb at each end of proposed driveway and knock out existing curb
• Saw cut existing pavement and break out to exposed existing reinforcement steel a minimum of 8 inches at proposed driveway intersection.
• Compact subgrade for proposed driveway connection from proposed saw cut at existing pavement to right-of-way line. Compact to 95% of standard proctor density (+/- 2% optimal moisture). The county engineer reserves right to require laboratory tests to be conducted.
• If more than one proposed driveway is built on the same property, said driveways shall be separated by a minimum distance of 20 feet (on roadways with curbs and sidewalks)
• Proposed area between driveways, from back-of-curb to sidewalk, and from sidewalk to right-of-way line may be concrete or dirt (on roadways with curbs and sidewalks)
• Proposed sidewalks shall have 1-inch board expansion joints or 1/2″ non-extruding preformed joint will be between sidewalk and curb, around fire hydrants, and utility poles.
• Reinforcing steel to be elevated a minimum of 3 inches above subgrade. (3 inch manufactured chairs are required with maximum spacing of 72 inches center-to-center each way).

driveway to sidewalk

driveway with curb

Isolation/Expansion Joints in Concrete

When building your own home, one of the items that will require your attention during the foundation/flatwork portion of construction is checking the use of expansion joints. Slab-on-grade isolation joints are used where a concrete slab meets another slab or other concrete structure, such as:

• Sidewalks or driveways adjacent to your homes foundation
• Between slabs-on-grade and surrounding foundation walls
• Between slabs and fixtures, such as drains, hydrants, lampposts, columns and other fixed equipment or structures.
• Between garage slab (or trough) and driveways
• Between driveway and sidewalk or roadway
• Between driveway or sidewalk and steps, patio, planter, or similar structure

tooled joint in concrete

Control (Contraction) Joints, Sidewalks and Driveways

Slab-on-ground control joints provide for horizontal movement of adjacent slabs, but do not allow differential vertical movement. Control joints allow for contraction caused by drying shrinkage and eliminate random cracking due to thermal volume changes. Control joints should occur at no more than 5 foot spacing for sidewalks and no more than 15 foot spacing for driveways.

control joint examples

Flatwork is placed after the walks, driveway, and patio have been cut by the tractor contractor (you may also be required to get a city inspection). It might be a good idea to pour back patios and pads for air condition compressors at this time also.

Materials required for this job consists of economy grade 2×4s and 1×4s, 1×2 and 1×4 redwood, 1×4 black joint material, 6 ga. wire mesh or #3 rebar, and concrete. All of this material can either be supplied by the contractor, or provided by you, but be clear about this during initial negotiations.

If you are contracting this work out, you need to provide a plot plan to the contractor so that you can ensure flatwork forms are installed in the proper location and to guard against encroachment on any easements. The contractor sets the forms, installs redwood (control joints set at prescribed intervals) and black joint (expansion material between separate pieces of concrete), grades the flatwork sand to assure a 4 inch thickness of concrete, sets the driveway in-turn, then places and finishes the concrete. Prior to setting forms for the driveway in-turn, the curb must be cut and removed.

You should visually check the flatwork for compliance with your standards (as well as city building codes) prior to allowing the contractor to pour the concrete. The in-turn inspection is also at this time and should be called in to the city with sufficient lead time to ensure the inspectors availability. The forms must be ready for concrete placement when the inspector arrives. Know the requirements for your community and, when possible, meet the inspector at the job site. Any corrective action specified by the inspector shall be corrected prior to concrete placement. Place the inspection certificate someone safe (inspectors are known to loose them).

The concrete finisher should be responsible for staying on the job site until the concrete has sufficiently hardened to protect against vandalism. Twenty-four hours after placement the contractor can come back and remove the form boards.

Pre-Placement Checklist for Flatwork Concrete

• Schedule flatwork and/or in-turn inspection, as required
• Check for 4″ concrete thickness in forms. Use additional flatwork sand to reduce the amount of concrete needed, if necessary.
• Check driveway in-turn for proper curb cut (as specified in applicable code requirements).
  • Cut should extend at least 6 inches into street
  • Allow for a 5 foot radius on each side of the in-turn
  • In-turn must be free of loose debris and no standing water
• Check the live ends on post tension cables to ensure that they do not interfere with the flatwork forms (examine garage and porch areas)
• Ensure that the patio is sloped to the nearest side of the lot for proper drainage (no more than 2 inches in 10 feet)
• Maximum step height at front & rear entries is 8 inches. Any greater height requires an added step(s)
• Check that the patio surface is 4 – 7 inches below the top of the slab
• Ensure the public walk is set in the right-of-way; lines up with existing sidewalk; and complies with local requirements.
• Check the slope of the public walk. It should angle 1 to 2 inches from rear edge to front edge.
• Check the driveway is 1 inch lower than the garage trough
• The forms must be ready for concrete placement when the inspector arrives (if inspection required). When possible, meet the inspector at the job site
• Rear entry stoop shall be 42 inches square. Use black joint at slab edge.
• A/C Compressor pad dimensions vary by unit installation
  • Single System – Typically 36″ x 36″ Concrete Pad (4″ thick)
  • Double System – Typically 84″ x 36″ Concrete Pad (4″ thick)
  • Ensure AC pads are physically seperated from the foundation to prevent vibrations and excess noise

Flatwork Placement Checklist

• Make sure you have a concrete washout location to be used by truck drivers
• Check and confirm black joint installation. Ensure it is level with the new concrete
• Check all joints for proper edging (i.e. picture frame use)
• Check for proper edging where concrete meets the form boards
• Check patio, stoop, and AC pads for trowel smooth finish
• Check drives/walks for a light broom finish

Checklist for Flatwork Concrete Post-Placement

• Check for concrete spillage outside of forms. Stack all spillage in one pile at curbside
• Ensure form boards have been pulled and stacked neatly
• Make sure all trash is in the trash barrel and construction debris is cleaned

cutting sidewalk

Following slab placement, form wreck and lot debris removal, you should schedule your tractor man to cut down the flatwork areas for concrete placement. This is also when the contractor responsible for cutting the curb for driveway and sidewalk placement will be ready to come to the jobsite. When building your own home, you should use the plot plan as your guide when having the walkways, driveways, and the patio cut down for concrete placement.

Concrete Curb Cutting & Cutting Sidewalk

You should bring in flatwork sand at this time to ensure that the flatwork forms will sit level (or slope as desired), and to keep flatwork thickness no more than 4 inches. Enough flatwork sand should be ordered (with sufficient lead time) so the tractor man needs to only make a single trip (this will save you money). Spread excess sand over the yard rather than piled on the lot or next to the street.

Cutting Sidewalk & Concrete Curb Cutting

Maximum driveway slope must be no greater than 14% (approximately 1.68 inches per foot). If you are building your home in a community with extreme lot gradients ensure a 14% slope is not exceeded. On lots that drain from front to back (FHA drainage type “C”) where the street is higher than any portion of the lot, ensure the driveway reverses slope at the established front drainage swale to preclude water runoff entering the garage.

Checklist for Cutting Curbs and Sidewalks

1. Check public walk location extends to the property lines on both right & left sides of the lot (in communities with public walks)
2. Ensure the finished height of the public walk is 1 – 1 1/2″ inches above the curb, but is adequately recessed to comply with lot drainage requirements. Do not accept situations where the flatwork creates a dam (especially between the entry walk and the slab)
3. Confirm driveway slope is less than 14 degrees (use the tables to help determine)
4. Ensure the driveway is cut so the form sits 1 inch below the lip of the garage trough
5. Check entry walk location cut per plan
6. Ensure the flatwork sand is spread to restrict flatwork to a nominal thickness of 3 1/2″ – 4 inches.
7. Check patio location for proper sizing & orientation, if applicable
8. Check slab for damage to the live ends of post tension cables (can be a factor with certain slab configurations)
9. Check the water meter, water service line, and front sewer clean outs for tractor damage.

Concrete Curb Cutting | Cutting Sidewalk