Tall Walls

One of the problems facing the homebuilder today is the quality of the wood you can get at your local dealer. He is not responsible for the problem, rather the problem is the lack of good wood (read old growth 200-300 year old trees).  The solution of course is to allow an increase in the cutting of old growth forests. I personally do not believe we should cut on more old growth trees to build a single home or for any other reason (my political comment for this newsletter).

The problem with real wood is that the young wood with its wide growth rings has a more frequent tendency to twist and warp after it is in place than the older trees that were available in the past. Unfortunately this usually happens after the drywall is up. This is especially true today as the ceiling heights continue to climb. Where once 7’ 6" was standard we now see commonly 9’ and even 10’ ceilings. These higher ceilings give the wood even more of an opportunity to give us problems.

As a point of fact we recently designed and built a home with one of our students that had in the living room very high ceilings, one wall was 14’ tall, the adjacent wall varied from 14’ to 18’. Because we are builders along with being teachers and designers I could just see these tall walls bending and bowing as the wet wood dried in the sun. I was convinced that these walls should not be real wood.

The alternatives were kiln dried wood, metal studs or engineered wood. Kiln dried wood is one: expensive and two: at least around here, extremely difficult to keep dry. Which of course, if you can’t you are back to the problems we started with in the beginning.

Metal studs were my great hope. No more old growth problems, straight and true walls, and a recycled material to boot. The metal studs are straight, don’t shrink or warp and make all kinds of subs happy, from the drywallers to the cabinet installer. So we should use steel studs, right?

Unfortunately, steel studs have a very serious energy problem. As I have mentioned before, heat passes in parallel through a wood wall, but steel studs short circuit the heat path causing serious degradation of insulation value of the wall. A 2x6 wood wall with R-21 insulation is an effective R-18 when tested as an assembly. 2x6 steel studs with R-21 insulation assembly, on the other hand, test out at a miserable R-8 equivalency. There are some fixes for this problem, ranging from steel studding with plastic thermal breaks to eight inch studs with R-30 insulation, just to be somewhat equivalent to the wood. Of course, all this just makes the whole steel assembly too expensive to be justified.

This leaves us with engineered wood studs, which is what I elected to go with. There are actually a number of options when it comes to engineered wood types available. I have not had experience with the first two products, "Finger jointed studs" and "Laminated Veneer Lumber" or LVL. Therefore most of the information I am going to give you on those two items comes from the article "Engineered Studs for Tall Walls" in the February 1997 issue of Journal of Light Construction, my very favorite and most informative magazine for the residential building trade.

Finger jointed studs have been around for some time. The studs are built up of short pieces of lumber glued together with acetate glue and are stamped "Stud Use Only". This is very important to be aware of because these studs can only be used for vertical end loaded applications. In other words they cannot be used for, say, a header. Although the glue is water resistant, not water proof, they should be protected from continuous water immersion.

My one concern in using these studs is that they designed for vertical loads. In the home mentioned above the over 14’ front wall is also filled with two stories of windows. One of the reasons I wanted continuous studding was to provide wind resistance. This (the wind) being a horizontal loading I would prefer something that is stronger in that direction then the finger jointed studs are reported to be.

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TANKLESS AND POINT-OF-USE HOT WATER HEATERS

We have had a lot of questions about tankless and point-of-use water heaters in our classes recently, so we thought we would bring our readers up to speed on this technology. Basically, the tankless system will provide unlimited hot water, since it heats the water only on demand. This, of course, is one of it’s major selling points. For the last person in line to take a shower, finding that the hot water tank has run out is a depressing experience. So for convenience, on-demand heaters supply an endless stream of domestic hot water at whatever temperature you select, which reduces the danger of scalding, a major cause of injury in small children. Flow rates vary between .5 and more than 5 gallons per minute (gpm), depending on the temperature of inlet water-usually assumed to be 50 or 55 degrees F-and heater output.

 In comparison, storage tank water heaters have to heat the water, then store it. Once the water has been heated, heat escapes up the flue and through the insulation around the tank.  Although the total time you might need hot water is only several hours a day, the burners turn on and off 24 hours a day. A very high portion of the cost of operating a storage tank type water heater is not associated with actual hot water usage, but with having to store it and keep it hot. And with no tank, there is no opportunity for the calcification and alkali buildup that shortens conventional tank life and reduces efficiency. Which brings us to the second major selling point, the energy efficiency. Tankless water heaters are 82% efficient, as compared to 80% for the first year for storage tank water heaters, which then decreases as the tank ages. In addition the life of a tankless is basically forever, whereas the tank will leak, on average within 10 years. Most manufacturers point to savings from energy efficiency of $100-$450 per year, depending on the type of on-demand heater and the type of conventional heater it replaces.

O.K., now that I’ve got you convinced that these are the best thing since sliced bread, lets talk about some of the disadvantages. The major disadvantage of tankless water heaters are their inability to service more than one faucet or appliance at a time. Most homeowners are accustomed to using more than one hot-water appliance at a time, which demands a relatively high house-wide flow of ready hot water. For example, a shower demands 2.5gpm of water at 120 F to supply a 3gpm flow at about 104 F. Washing dishes demands an additional 2.5gpm. Most conventional tank water heaters can easily supply enough hot water for both activities-until you run out.   However, the smaller tankless units cannot supply this volume of hot water.

Let me give you an idea of the different types of units available, their cost and what they can do. This information is on Aquastar which is made by Bosch, and is courtesy of Tony at George Morlan Plumbing in Tigard who supplies most of the plumbing fixtures for our clients.

Model 125B-this unit is designed for domestic use and can supply 3.3gpm at an incoming temperature of 55 F (as of 1992 all showerheads sold have a maximum flow rate of 2.5gpm). As you can see, this would supply any one faucet or appliance.

Model 125BS-has been designed to work with preheated water. When the heater is fed preheated water, the thermostatic control will sense if the water is already hot enough. For instance, this is a particularly good application for solar water systems, where the water is warm but not warm enough for a really good hot shower same time. As you remember, this was the major drawback to the first models. This method of heating water combines the use of a storage tank with the efficiency of a tankless. In this case the tankless is plumbed to a storage tank in a recirculating system Figure 1. The advantages of using the two together are you don’t lose heat through the vent pipe of the tank, you have in many cases twice the recovery rate of a tank water heater, and you still have endless hot water, you  have the availability of a lot of hot water whenever you need it. The disadvantages are that now you’re back with a tank that loses heat when you store water in it.

Model 170-this is the largest of the Aquastar line and is used for commercial and industrial water heating and is perfect for filling large whirlpool baths or providing hot water for 2 simultaneous showers. This model heater can deliver a flow of 5.3gpm at a shower temperature, or 2.95gpm at a 140 F temperature.

Model 38B-this unit is a very small heater which is ideal for boats, recreational vehicles, camps, and portable applications such as farms and ranches. It can supply 1.3gpm for a 45-degree rise in temperature.

The cost of these units is also somewhat higher than a conventional hot water heater, although you must take in to consideration the savings in energy which are substantial and the fact that it will not have to be replaced. All parts are replaceable, but the whole unit will last forever. Here are some prices from Morlan.

While on the subject of of instant water I wanted to include the electric hot-water dispensers that are small enough to fit in the kitchen sink cabinet and plug into a standard duplex receptacle. Most come equipped with a ½-gallon reservoir and with an integral spout that mounts in the sink deck or countertop. Although some models can also supply cold and warm water, most dispenser thermostats are adjustable between 140-200 F, and most models can produce from 40-60 cups of 190 F water per hour. That’s enough for instant coffee, tea, hot chocolate, and powdered soup. But flow rates re too low-and the water too hot-for general purpose use. In fact, many spout handles protect against scalding by springing back into the off position unless held open. The cost on these units runs from $154-190 from Morlan. We have been installing these in many of our mid-upper end homes. They are very convenient and relatively inexpensive.

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KITCHEN DESIGN IV

Lighting the Kitchen

Let's face it: Kitchens are expensive. In our continuing series on kitchen design, we are going to give some space to one subject that's often overlooked in kitchen remodels and in the design of new kitchens: lighting. Too often the choice and placement of light fixtures is based on whatever happened to be on sale that week at the
local home center.

A well-lit kitchen, on the other hand provides adequate illumination to the general kitchen area and to specific work, or task, areas and renders the colors of the kitchen's components accurately. Lighting can be a complex
subject, with mathematical formulas and unfamiliar words. And there are many variables that affect the results of any lighting scheme such as wall colors, the reflective quality of surfaces, the amount of sunlight entering the room, and so forth. While it is beyond the scope of this column to cover lighting in depth, there are some concepts you should be familiar with so that you can talk intelligently to your lighting consultant or electrician.

General and Task Lighting

Two types of lighting are critical to any kitchen: general and task. General lighting provides enough illumination to walk about the room, while task lighting furnishes much brighter illumination to working surfaces, such as countertops. Both types should afford even coverage, leaving no dark or bright spots between lamps. This effect is achieved through the proper spacing of lamps. ("Lamp", as used here refers to any manmade light source, while '"fixture" is the housing or assembly that holds the lamp).

Figure 3

The objective in lighting a kitchen is to have continuous light coverage at 36 inches above the floor, normal countertop height. Since the room is 120 inches wide, each of the two laps must cover 60 inches of countertop. Here the first fixture is 30 inches from the wall.

General Lighting. A lamp produces a cone-shaped beam of light that is measured by its beam spread, or width. Different kinds of lamps-such as pin spot, halogen, flood or fluorescent-produce a beam of light specific
to that lap. For example this beam may range from a low of 7 degrees for a pin  spot to a beam spread of 85 degrees for a flood. It's the width of this beam that determines the spacing of fixtures.

Half-cone method. Figure 3 represents a kitchen cross-section with two ceiling height fixtures. The work surfaces will be at 36 inches-which I want my general lighting to illuminate. Since the room is 120 inches across (10 feet), to provide uninterrupted illumination each light cone must be 60 inches wide at counter height (120 inches divided by two fixtures). A half cone is 30 inches wide. Therefore the first fixture would be 30 inches from the wall and the spacing between fixtures 60 inches. The same result is obtained by dividing the number of half cones (40 into the width of the room, 120 inches).

It doesn't matter how many fixtures are used, the half-cone method will always yield even spacing. But if the cones overlap too much, there will be a bright spot: if they don't meet, there will be a dark area. For example
using the three fixtures spaced 40 inches apart would produce overlapping bright spots 20 inches across, while a single fixture would leave a large dark area.

Figure 4 shows another kitchen elevation. In this example, I’ve chosen a lamp with a 55-degree beam angle, which is commonly used in the kitchen. In a typical 8-foot ceiling, the lamp has a spread of 62 inches, 36 inches from the floor (this information was provided by the lamp manufacturer). The beams intersect 6 inches above the counter, ensuring good coverage with minimal bright spots. The lamps have been shifted to the right from those shown in Figure 3: the left fixture is now 39 inches from the wall. By making this move, the edge of the cone does not create scallops on the face of the wall cabinets. Undercabinet lighting furnishes the counter with brighter task lighting.

Recessed trim. Too often, recessed fixtures are outfitted with black step baffle trim, which absorbs 50% of the light generated by the lamps greatly reducing their efficiency. Black trim also contrasts with the typical white kitchen ceiling, which breaks up the ceiling and draws the eye upward.

Instead, use white trims. Or even better, use mirrored Alzak or clear specular reflectors. White trims still absorb about 30% of the light, while the Alzak allows virtually all the light to exit the can. Also, the mirrored
surface reflects the color of the ceiling, causing it to "disappear" better than white trim. While Alzak fixtures are more expensive, fewer of them are needed because they reflect light more efficiently.

Counter Lighting. Good task lighting provides adequate even illumination to the counter surface as well as the backsplash, which contributes a lot to the kitchen's aesthetics, particularly if the backsplash is tile or wallpaper.

Counter lighting is usually installed behind a light valance attached to the front edge of wall cabinets. I like undercabinet light fixtures that space the lamps 2 inches on center. Using this spacing allows complete coverage across the bottom of the wall cabinets, distributing light evenly on the counter and the backsplash. Look for fixtures that use xenon-gas-filled festoon lamps; they look like "fat" automotive fuses These install quickly in lengths up to 12 feet that can be trimmed every 2 inches. The resulting even field of light
reduces visual "chop" and creates the illusion of a larger room.

In contrast, undercabinet fluornescent fixtures using "pencil" laps are available only in limited sizes and leave gaps between fixtures, rendering dark areas on the counter and backsplash. They also yield very poor color, giving a unnatural look to food. Where there are no wall cabinets, such as over islands or above window sinks use cans or hanging lamps.

Color   

Lamps must reproduce the colors in the room properly. Without a lengthy discussion as to how it all works, keep these guidelines in mind when talking with your electrician or lighting consultant. Lamp specifications
are available from lighting supply houses.

Task, accent and art lighting-Halogen lamps, PAR halogen and MR16 lamps (small low-voltage lamps) do an excellent job. For art, MR16 lamps are preferred because they throw their heat back and away from the art.

General lighting- Use PAR halogen lamps or compact fluorescents. Compact fluorescent lamps should be about 3,500 Kelvin (they range from 2,700 to 6,500 Kelvin) to approximate the color of halogen lighting and may be used elsewhere in the room. Doing this ensures that all like colored objects  will look the same. When using other types of fluorescents, remember to use lamps that are over 80 CRI (color rendition index) and between 3-3,500 Kelvin.

Making a layout of your kitchen with the lighting drawn out will enable you to see where the lights will overlap and where the dark areas are. This is a must if you are not using a professional lighting designer.

Figure 4
 

In this kitchen scenario, the lamps have a beam spread of 55 degrees, which provides 62 inches of coverage at countertop height. The fixtures are installed 56 inches apart, producing a 6-inch overlap on the countertop. The first fixture has been shifted to the right to eliminate "scallops" on the wall cabinets,  placing it 39 inches from the wall. Undercabinet lighting has been  installed for task lighting.

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