The Important Things You Will Need to Know About Additions

Let’s start with an easy one.  You’d like to enclose that covered patio and use it as an extended family room or possibly use it to help expand the kitchen.  There are plenty of reasons why you might consider this.  Here are the things you need to know.  I’m writing this specifically for the areas we serve in Clark County, Nevada including all of The City of Las Vegas, Henderson and all the communities within the area like Summerlin, Green Valley, The Ridges, Queensridge, Sienna, The Palisades, Canyon Run, Inspirada, Anthem and Red Rock Country Clubs, MacDonalds Ranch and everything in between.

Here are the items that most homeowners have no idea they will encounter:

  1.  The slab that your patio was built on (for the most part) does not have plastic or waterproofing underneath it.  This is critical because we (contractors) are not allowed to pour additional concrete on top of the already existing concrete deck.  Remember you are going to have this as new living space accessible from your home’s interior.  In order to make this happen, we have to tear out the old concrete and pour a new slab that will be level with the existing floors in your home.  Included with the new slab is having the correct type (type 2) of material below the slab with new plastic waterproofing, drilling into the existing slab and epoxying steel rods approximately 6” or more into the existing slab.  This requires a 3rd party inspector to verify to the County or the City that the steel rods are embedded properly.  They will have a visqueen (plastic) barrier below and then either steel rebar or steel mesh (or both) included at specific spacing for strength and then the concrete will be poured.  If a footing is required then the steel will be installed in the footing.  The slope will be removed and the slab will be leveled relative to the interior floors.  The step down threshold will now be eliminated and that elevation difference will be transferred to the outside perimeter at the location of a slider or French Door (if you have access to the outside)  If you want this room closed with no access to the outside then the elevation will be maintained all the way across the floor.  I am not allowed to use a waterproof coating over the original patio or add visqueen above the existing slab and pour a new one on top.  The old slab has to be removed prior to starting. 
  2. Generally, if you stay under 600sf that will save you additional expense.  If the slab is more than 600sf, you must provide a pad and you don’t even want to know at this point how much work is required to do that but it includes excavation and geo technical documentation.  I’m sure you’ve seen this before but might have not realized what was going on.  Have you ever driven by a new home lot right after they started clearing the land and before building and looked at the pad?  Now you have some idea of what might be involved.  Don’t go there unless this area really needs to exceed that square footage.
  3. Structural issues line up next.  Engineering will be required to determine the size and strength of the footings that will support the perimeter lines of the project.  If the addition is 20×20 then you will have two walls tied into the existing home and one outside wall so the footing will be 60’ in length.  As mentioned in Item 1, the new slab has to be tied into the old one by drilling and epoxying steel rods at the connection in addition to rebar.  Other issues begin to surface now starting with the roof.  Some roof areas are all trusses, others may be stick framed back to join the roof at a higher level.  The best way to visualize this would be in this type of example.  The outside wall of this new area we want the ceiling height at 10’ and we typically try to match the pitch of the existing roof.  Unfortunately 10’ is the height of the outside wall of our house and we have to gain more height.  We gain the height by (one method….shortened for length of that article and the fact that I can’t accurately cover everything here) is we have trusses running the length of the addition and they tie back into the house with a stick frame assembly that connects the new roof to the old.   We do this with by constructing a gable roof.   A gable roof is the classic, most commonly occurring roof shape in those parts of the world with cold or temperate climates. It consists of two roof sections sloping in opposite directions and placed such that the highest, horizontal edges meet to form the roof ridge.  Anyway, the point is we need structural and architectural drawings to define the space, how it interacts with the existing building, and how it is supported.  Our architect’s job is draw this out and define how the addition is built and it’s the job of the engineer to make sure that we have used the correct materials and confirmed the strength and support needed to build the addition. 
  4. Siding, stucco, trim materials and their construction and placement will be part of your architectural plans.
  5. Electrical code must be followed for the number of outlets and their placement.  Typically this is not a big issue for lighting and outlets as they don’t consume a huge amount of electricity but the electrical plays a major role in your HVAC.  We’re going to be checking the size of your service panel and making sure that we have all the bases covered. 
  6. HVAC:  This new space must be heated and air conditioned in the same manner as the rest of the home meaning there is a system in place to provide both heat and air conditioning and that it is permanent.  Wall hung air conditioners are not permitted to serve this purpose.  Should the day come that you sell this home, all the systems must be intact, working, serviceable and accessible.
  7. Access and Egress issues are handled by our architect but to shorten this, the keynote here is fire department access and you being able to exit the building in the case of a fire emergency.  That means there are specific guidelines for window sizing, accessibility, lighting and a number of other items all designed to protect and serve the residents. 
  8. If the new area will serve as a kitchen there are other issues with underground piping, draining, conduit, wiring, electrical panel size, sewer lines and water supply as well as the new space must meet the environmental codes for insulation, glazing etc….

This is not meant to be an exact check list of every item involved with an addition and how you should build it but more as a reference to a lot of items that most homeowners are unaware of.  These are things that can determine the costs of your project.  This is where your Contractor and his team of architects, engineers and professionals are there to help you avoid the pitfalls and have a successful project designed to last for years of service and enjoyment and to provide increased value to your home.