Basements (8 of 9): Floating Walls

Floating Wall Detail

“Floating walls” are not like “Sky-hooks”.  It is not an imaginary term used in jest to explain how a building will stand.  Floating walls are real and very necessary for basement finishing.  This simply means that the wall does not extend fully from floor to ceiling.  Don’t fret.  That doesn’t mean they are not solid or that they don’t provide separation from one room to the next.  There are two ways to construct a floating wall.  The most common and preferred method is to hang the wall from the ceiling, leaving a gap at the base to allow room for the concrete floor to heave if necessary.  As discussed in the previous post, treated wood is secured to the floor and a gap of about 1”-2” is provided above this.  The “floating wall” suspended from the ceiling is then secured laterally by tie rods into the base plate penetrating the floating base through a slip hole.  (See the detail for better clarification.)  This is preferred over another method of providing the gap at the top of the wall.  If the gap is at the top than any floor movement will result in cracks in the wall finish because floors do not heave evenly.  So remember, “floating walls = good”, “sky-hooks = bad”.

Basements (7 of 9): Exterior Walls

Most people, when finishing their basement, want to cover the exterior masonry walls.  After all, who wants to stare at a mass of rough, gray, cold wall?  Furring out the wall (built-out framing) will remedy this quite nicely, but before this is done one must verify that there is proper drainage at the base of the wall.  This is not easy to verify because the drainage is buried under several feet of dirt.  If you have a newer home you can check the plans on file or check with the original builder.  The reason you want to have proper perimeter drainage is because you will not be able to tell if there is water leaking through the wall once you have covered it up.  So, assuming you have proper drainage you have several ways to finish the walls.  One that is not recommended but seems to be popular with most do-it-yourselfers is to “glue” drywall to the surface of the concrete.  (Yikes!)  This is not recommended because any movement of the wall will result in cracks in the finished material, which inevitably results in pounds of mud (or drywall joint compound) being plastered over the crack over many years.  Another, only slightly better method, is to attach furring strips to the concrete and then secure gypsum board (drywall) to the furring strips.  A couple of flaws with this is that most do not think of providing treated wood (as discussed in an earlier post) and with the furring strips securely fastened to the concrete you still have the same issue of cracks due to any wall movement.  For the best results, use the floating wall method described in the previous post with an air gap of about one inch between framing and concrete.  This allows the wall and floor to move without interfering with any finishes.  The expense is a little more up front, but you don’t have to worry about trying to cover-up the mistakes of poor installation over the years with mounds of mud.

Basements (6 of 9): Treated Wood

Finishing your basement is more than throwing up walls and covering them with drywall.  What most people don’t realize is that wood has a chemical reaction when placed next to concrete.  This reaction deteriorates the wood in a short period of time and will create many unwanted issues.  Fortunately, we have become wise in some things and discovered that treating wood with certain chemicals will prevent these reactions, making it possible to use concrete and wood together to create lasting structures.  So, don’t be fooled by someone claiming they can finish your basement for you simply because they can swing a hammer.  You may find yourself with very costly repairs in the near future.

Basements (5 of 9): Plumbing

Most home builders have good intentions when they provide rough plumbing layouts in basements.  This is both good and bad.  It is good that you don’t have to put the expense of tearing up concrete to put in your own plumbing, etc.  Most fixtures have been considered and can be worked into the space they have provided.  However, this also limits the layout of the entire basement.  You have to put the bathroom right where they have chosen and hope you can be happy with the configuration of rooms that will fit around it.  Even the bathroom can only be configured the way the rough plumbing is laid out.  The location of the door is usually implied as well, so all areas are predesigned in a sense because of the plumbing configuration.  The savings of not having to put in your own plumbing, etc. could be worth the limited design potential.

If you don’t have rough plumbing provided, this too is a blessing and a curse.  If you are simply designing an additional living room there may not be a need for a bathroom or plumbing.  In most cases, if someone is planning to make use of their basement, they usually have additional bedrooms, fitness rooms, theaters or other spaces in mind.  For convenience (especially with bedrooms) providing a bathroom is essential.  This means you must cut through existing concrete (unless you are fortunate to have a framed floor over crawl space) and run new lines (supply and waste) to the new locations.  Most basements will have floor drains provided and the water heater is usually located in the basement.  This is an advantage which can be utilized, and if planning is done correctly near existing plumbing supply lines, the excavation, demolition and repair will be minimal.

So the long and short is that there are advantages and disadvantages to having or not having rough plumbing provided.  In either case, a good designer can take advantage of the situation and give you the best solution to fit your needs and the space provided.  Don’t be afraid to explore the options – paper is cheap – so find the design that you will love!

Basements (4 of 9): Insulation

Insulation in the basement seems like a foolish thing to do.  After all, what could provide better protection then a very thick and heavy wall?  The truth is that concrete has one of the lowest values of insulation.  In fact I am certain that everyone who has spent time in basements has noticed a drop in temperature.  This is not merely because it is below grade.  This is the result of poor or no insulation.  The basement is a conditioned space and should be comfortable just like the rest of the house.

 Insulation values are rated as R-values.  The higher the R-value, the better the insulation.  Current energy code requirements state that exterior walls must have an insulating value of R-19 or better.  This is so the expense of heating a home is not lost (or at least is greatly reduced) due to thermal failure in the walls.  The same should hold true for basements.  One should not “put up” with the discomfort of a chilly basement simply because that is the way it has always been.

This brings me back to R-values.  Standard Batt insulation for a 2x6 exterior wall has a value of R-19.  Compare that to concrete which has a value of R-0.08 for every inch.  For a typical basement foundation wall of 8” that is a total value of R-0.64.  YIKES!!  Why wouldn’t you want to insulate your basement when so much energy is being lost through the walls?  The best way to prevent this loss is to provide furring (built-out framing – more on this in a future post) at the perimeter wall and fill the cavities with insulation, just as you would any exterior wall above grade.  The expense will be well worth every penny when you can spend every moment in your basement in comfort.

Basements (3 of 9): Head Clearance

With how frequently basements are finished in Colorado, it is odd to me that there seems to be very little forethought regarding their function when the home is designed.  Often there is a great deal of tweaking and adjusting required to make the spaces work. 

One thing that must be considered is head clearance.  In order for a basement to be considered habitable, most municipalities in the Denver region require a minimum head clearance of 7’-0” throughout the entire area proposed for living space.  This can be a challenge in older homes when the basement (or cellar) was intended only for coal storage or other utilitarian functions.  Some municipalities also stipulate that only a certain percentage of the ceiling in each room can be permitted at 7’-0” (or whatever their regulations require).  With the use of dropped beams this can be a serious challenge even in newer homes.  The key is to do some pre-planning research so you don’t have to pay for costly redesign fees.  Of course, most architects and residential designers will perform this task before a pencil is set to paper.

The next consideration is head clearances at doors or doorways.  The code requires that all doors, doorways or openings intended for passage are to be a minimum of 6’-8”.  Some municipalities allow for exceptions in finishing basements, again, because of the standard and common use of dropped beams.  Others are more stringent and will not allow for this exception.  This could be a real issue and must be addressed before any design work is to be considered.  This is also something that can easily be overlooked in design review and create major problems during inspection.  At that point you are entirely at the inspectors’ discretion, which is not always in your favor.  Planning ahead and placing doorways away from dropped soffits and beams may be inconvenient, but it could save you a lot of headache and expense later.

Even with the challenges of designing around beams, the basement can add some much needed space and function.

Basements (2 of 9): Egress

Egress is a term that is used heavily within the building and construction industry, but for most outside of this field it is just a funny sounding word.  Simply put, it is the means to exit a building.  This is important in residential design, especially in bedrooms and basements.

The first thing to understand about egress requirements is that even though it is important to provide a means to exit a building, it is more important the opening is large enough for a firefighter to enter the building while carrying all their necessary equipment.  This is why within the building code there are many stipulations regarding the minimum dimensions and location of openings in any given room. 

Some, even within the industry, mock some of these regulations.  For example, a casement window (windows that are hinged and open with a crank from the inside) have minimum dimension requirements based on the open position of the window.  The standing joke states that the firefighter must first break the window and then crank it open to gain entry.  The truth is that if there is a fire and the window is already open then the clearance must be adequate for proper egress and fire rescue.  Although some code requirements seem mockingly hilarious, there is a legitimate reason for the code and it could be the one that saves your life.

Since the access to most basements is a stair leading from the main level of the house, how this translates in basement design is that a means of egress must be provided from each bedroom and the main living area which leads directly to the outside.  The sill of an egress window must be within 42” above the finished floor (and I would argue this should be lower for rooms intended for smaller children).  There must also be a permanent ladder secured to the side of a spacious window well.  To most people the first image to come to mind is an ugly, pre-manufactured, corrugated steel well with a matching hideous ladder.  This need not be the case.   As long as the well meets the minimum dimensions and stepping is provided that does not exceed required dimensions, then the sky’s the limit on possible well design.

So, since you have to have a window well, think of all the possibilities to personalize it and let the design become a feature of your basement and not something to hide with drapes or the dreaded blinds.