Landscape Grading and Drainage

This summer has been focused on the landscape and exterior of Tandem House.  We have two open permits that have yet to be closed pending Zoning and SUDP (Sewer Use and Drainage Permits) final inspection and approval.  Once these permits are closed then we will finally have our Certificate of Occupancy.

Zoning has already confirmed that the building fits within the bulk plane and setback requirements (among other things), but a few items have yet to be done.  In order to get our Zoning permit closed the City wants to see that all landscaping be complete, that no lingering construction material be on-site and that they approve all exterior lighting.

The Sewer Use and Drainage Inspection ensure that the flow of water is away from the house and handled either on-site or directed properly towards the alley.  It also dictates that sump pump discharge is handled on-site and inspected per the City’s detail.

A good landscape design understands that both subjects go hand-in-hand.  A successful landscape design acknowledges grading and drainage from the very start because it dictates cut and fill, site retaining, steps, access points, circulation and the flow of water.  A major factor in our landscape design was dictated by the final Finish Floor Elevation of the house which is 3.5′ lower than what was existing.  Hense excavation and the hauling of dirt off-site was a huge endeavor and a major cost.  This was a big learning experience for myself as a landscape designer.  From this personal experience as the homeowner, I now understand the importance of limiting the amount of cut on-site by finding creative and resourceful grading solutions that limit the need to haul dirt away.  In the middle of a construction boom in Denver, hauling dirt away is more expensive than ever because everyone is building basements and underground parking.  Most construction sites are getting rid of dirt (cutting) not filling.  Hence the problem.  Dirt has to be loaded one truck at a time and hauled away 40 miles north.

This Spring we prepped the site for landscape.  All major excavation was complete so we began by installing a wood retaining wall at the south property line.  The wall now holds back the 3.5′ of dirt from our neighbor’s yard; preventing it from eroding or collapsing onto our site.  With the wall up, it allowed us to prepare for what would become a large rain garden.

Step 1:  The Rain Garden

The rain garden is the foundation for site drainage and a major landscape component.  To build the 200 SF rain garden we had to excavate another 2.5′; that’s on top of the 3.5′ that was originally excavated.  Once the garden was dug, we directed roof run-off via downspouts.  As the water exits the downspout it enters a catch basin and that leads under the now sidewalk and into a dry rock well at the bottom of the rain garden.  We also directed the sump-pump water to the rain garden.  If there is ever excessive groundwater from a rain event, the sump will pump the water up and away from the house foundation into a second dry rock well at the bottom of the rain garden.

Once the water was directed to the rain garden we filled it with a soil mix that promotes drainage.   The mix is made up of 30% sand, 25% compost, 25% topsoil, and 20% clay.  To complete the rain garden we planted two Rocky Mountain Glow Maples and a mix of Colorado native grasses (little bluestem, blue grama, and switchgrasses among the ten different species).  This rain garden is not irrigated and once established it will be fully supported by natural rainwater events.

Step 2:  Fine Grading & Artificial Turf Prep

Below is our SUDP plan.  This is subsequent to the more detailed grading plan and shows where water is flowing.  The ‘infiltration swale’ is the rain garden.  Downspouts and flowlines (FL) show where water is being directed away from the house foundation.

SUDP

Below are images that show the aggregate base for the artificial turf detail and the sloping landscape away from the house with french drains that lead runoff towards the rain garden.

We chose not to irrigate our landscape and to make that come to fruition we installed an artificial turf lawn.  The manufacturer is synlawn which is a great product.  The proper foundation for artificial turf is crucial for efficient drainage.  To prep for the lawn, we removed 4″ of earth where the turf is installed, filled the area with 3″ of 3/4″ aggregate, compacted that and added 1″ of pea gravel.  We lined the area with a steel edger which completed the prep work.  To install the lawn we rolled it out in place, made a few cuts and seams and pinned the lawn down with 6″ non-galvanized steel nails.

The lawn is now a fantastic place for our one-year-old daughter to play.  We completed it just in time for her first birthday!

 

Home Tour Part 1 – The First Floor

Although the Tandem House is not completely done we decided to move in; just in time to host Thanksgiving with our family.  Its been a whirlwind of a month as we not only needed to furnish the entire back tandem house (new), but we also prepared the front (old) house to rent as a short-term rental on Airbnb.  We figured there was no reason to delay getting monthly rental income if we are ok living in the tandem house while finishing the final touches.  While we live here we will continue to install remaining interior doors, baseboards, door trim, backsplash tile and a number of other smaller tasks.

For now we are relishing in what we have done and not so much in what hasn’t.  Its been a huge accomplishment to get to where we are and we want to enjoy it.  We’ll keep it low key through the holidays and get back at it in the new year.

But lets get to the good stuff; a photo tour of the house.  As a reminder, the home is 2400sf in all, with 4 bedrooms and 3-1/2 baths.  The adjacent plan of the first floor shows the open concept living, kitchen and dining area, the 1/2 bath off the mudroom and the 1.5 car garage.  The stairs lead down to the basement and up to the second floor bedrooms.  The contemporary architecture of the home is complemented by a mid-century modern interior decor.

 

 

Untraditional Stairs and Bold Flooring

When Scott and I were dreaming about building our tandem house, we used to spend the weekends going to open houses in the neighborhood.  We were curious to see the standard of material finishes that we would be held to in order to compete in the highland residential market.  There was one house in particular that had these chunky wood stair treads and metal fabricated railing.  We loved the untraditional look and knew that we wanted a similar aesthetic in our house.

Little did we know how complicated planning, designing, fabricating and installing these stairs would be.  Although it was a long process, we couldn’t be more happy with how they turned out.  We went with solid hickory treads that Scott finished with a natural polymer-based finish.  After three coats and sanding in between, the treads were ready for install; just in time for Thanksgiving.  Our family could rest assured that we had railings.  Not only did the stairs look fabulous but they were safe for all the little ones to run up and down when they played hide and seek!

We made a bold chose by going with concrete floors in our main living space.  Although concrete floors are not uncommon these days, it took some extra planning because the floor sits above our basement.  Meaning, the joists below the floors had to be doubled up in order to support the structural load of the concrete above.  See our previous post on the pouring of these floors.

After ten passes with a diamond grinder and a matte protective finish, the floors are beautiful and have a complex natural look.  Even better, they are seamless, collecting little to no dust.  They are smooth and easy to clean!

On the second floor, we went with solid character maple hardwoods.  We love the natural and bold look of these floors that are a far cry from the more traditional oak flooring that you see in many Denver homes.

We went with porcelain hex tiles in the bathrooms and laundry room which ties in the concrete look from the main floor.  And last, we chose carpet in the basement because it gives a comfortable and homey feeling for our guests when they come to stay with us for the holidays!

Solar

This past Thanksgiving week our solar pv system passed a final inspection by the City. Going forward our Xcel Energy bill will start metering the solar power generated and used.   We couldn’t be more excited to start using power off the grid and to start tracking our savings.

We ended up selecting flexible solar panels by Miasole call the FLEX series, specifically model FLEX-02N .  These panels are an ideal solution for our standing seam metal roof since these lightweight modules directly bond to the roof between the metal ridges.  Not only do they offer a clean, sleek aesthetic but the modules will provide more than enough energy with the 16, 125-watts panels.  These lightweight panels reduce the structural load of a typical panel array and they minimize wind resistance with its flat profile.  Our generated energy will be stored in the SMA 3.0 KW inverter which has extra capacity in case we want to add more panels at a later time.

 

 

 

 

SMA 3.0 KW INVERTER

Landscape Site Work

The landscape site work is definitely an orchestrated process that has many phases to follow.  The images below give you a sense of where the site stands and we’ll continue to show the evolution.  The site work to date is outlined below:

  1. Demolish the existing porch and awning
  2. Excavate and form a retaining wall between the front and back house
  3. Install a new electrical panel and meter box on the existing house and bury the overhead utilities
  4. Layout and build formwork for concrete path and stairs that will connect from the City sidewalk to the new house
  5. Plant Trees (14, Skyrocket Junipers).  The evergreen trees will grow to form a 20′ privacy wall between the front and back house

 

Insulation and Drywall

The reward after months of interior framing and particularly the not so fun part of framing out ductwork, is drywall!  Now that drywall is up; there is a real sense of space that we have been longing to experience.

But before drywall went on the walls we did one final pass at sealing the building envelope which included foaming around windows, doors and ductwork.   The garage walls and ceiling were spray foamed to limit air exchange into the house.  Last, we used batt insulation between the first and second floors and again along the master bedroom wall to limit sound transfer between the spaces.

Once insulation was in, drywalling began.  Although it is not yet finished, we feel that this has been the biggest impact.  We opted for a level 5 finish which is the smoothest result. You’ll see the process in the photos below that begins with hanging drywall, taping and mudding the seams and finally using a big roller to mud the entire wall.  After each mudding, the walls are allowed to dry overnight and sanded the next day.  We are happy with the result so far and excited for paint.

Standing Seam Siding and Roof

While Scott completed odds and ends of interior framing, to prep for insulation and drywall; the awning, metal roof and siding were getting installed. Scott and his step dad Jeff spent the weekend building the awning that will provide protection from the outdoor elements.  The awning will eventually be cladded in metal and wired for lighting and outdoor speakers.

Roof installation was delayed for months because the subcontractor was so busy (a sign of Denver’s booming construction).  This has made it difficult to stay on schedule and keep momentum going when contractors are so hard to track down.  Additionally, it leads to a ripple of delays because things like interior insulation and drywall are dependent on a completely dried in house.  Luckily we finally got the roofing contractor to site and now things are moving along faster than ever.

In just a week, the metal roof and siding went up.  We chose metal standing seam material because it is a superior product that will stand the test of time, and will allow easy installation of our thin film solar panels.  Our original design intent was to use flat panels on both the roof and facade (for a clean look) but upon recommendation from the contractor; we ended up incorporating striated siding.  Since the structured wall panels are not completely flat and uneven in places, the metal siding, if not rigid enough, will bow out or dimple over time.  We obviously did not want that to happen so we chose to incorporate striations to make the siding more rigid.  We kept the roof panels flat for two reasons: 1. The roof is flat so we don’t have to worry about imperfections in the metal over time, and, 2. We will be installing solar panels that will adhere to the flat faces of the roof panels.

Standing seam siding is installed on all north and south facades.  The metal material will hold up well over time as the hot southern sun beats down on it.  We will complete the exterior look with a cedar wood rain screen, installed on all west and east facades (stay tuned).

Interior Progress

Scott is really excited about making our home smart, comfortable and efficient so the install of plumbing, electrical, heating and cooling systems has literally brought energy and excitement into the space.  When it comes to heating and cooling we will be using a Fujitsu electric zoned mini-split system.  Instead of central air, the new HVAC system uses wall-mounted units throughout the home so that we can focus on heating or cooling individual spaces rather than the whole house at once.  The system eliminates complex and expensive ductwork and will function much more efficiently than traditional central air.  What is a mini-split?  Check out this Fujitsu article that explains how it works.

In addition to the systems install, we have new metal fabricated stairs, a garage door and the big event this week was the concrete pour on the first floor.  Lots of great pictures to check out below!

Sewer and Water Line Install

Installing a new sewer and water line to a tandem house is one of the major incurred expenses (basement is a biggy too) that could make you lean towards building an ADU (accessory dwelling unit) instead.  Because our lot will be subdivided, the front house and tandem house will be legally independent of each other; requiring that all utilities be tied into the City’s grid and not linked with the front, main house.  With an ADU you don’t have to tie utilities (sewer, water, gas, electricity) into the City’s main sewer and water lines, making the process less disturbing and saving a lot of money upfront.

However, if you can burden the upfront cost, we are still firm believers that the benefits of building a tandem house has major advantages over building an ADU (check out ADU vs. Tandem House).  Case and point, we just had the tandem house appraised (at ~60% completion) and the appraisal value came in better than we could have expected.  Giving us the confidence that all the inconveniences of construction will be worth it in the end.

Below are some images of the sewer and water line install that took about 3 days.