Ask a Green Builder: Dennis Allen

Dennisallen018smallEver wonder about the durability of bamboo floors? The benefits of thicker insulation? The rebates available for adding solar power? The cost vs. value of new windows?

Dennis Allen, a nationally recognized green builder in Santa Barbara, is on hand today and tomorrow, the 29th and 30th, to answer your online green remodeling questions.

Topics of interest are:

• energy efficiency
• improving indoor air quality
• sustainable and durable materials
• water conservation
• construction waste management

You can read more about green building on the Allen Associates website.

Click below to ask your green building question.

9 Comments on Ask a Green Builder: Dennis Allen

  1. Kathy Price-Robinson

    Thank you Dennis Allen and your staff for answering our green building questions. We appreciate the depth of your knowledge on the topic. And we look forward to having you back again in a few month. Thanks again!

  2. Dennis Allen

    Jeannie –
    Water collection systems can be a challenge in coastal California where the majority of rainfall occurs during a three or four month period (January to April) followed by many months without any rain at all. Our rainstorms typically deliver lots of water over very short periods of time. The questions that arise are whether you can collect enough water during the rain period and, then, how long that stored water will last during dry periods to warrant collecting it in the first place. It gets down to how large a storage tank you can install and still have the system be useful and affordable.
    Another issue you must consider in designing a water collection system is including a method for diverting “first flush” water to reduce sediment buildup and eliminate the potential for bacteria and other contaminates from entering the system. You also want to design the system to keep mosquitoes and vermin from getting in. Your system should also include an overflow device that will divert water from the storage tanks into your yard or existing storm water collection system when the tanks are full.
    It may be more beneficial and cost effective to design your landscape with low water using plants and, even more importantly, with permeable surfaces, bioswales or retention systems that will reduce runoff and allow water to slowly percolate back into the groundwater table.

  3. Dennis Allen

    Dale –
    Cellulose insulation would be an excellent choice for you. It is made from 100% recycled newspaper and other paper products, is fire resistant, non-toxic and environmentally friendly. And, it can be blown into existing walls. Because it fills the entire wall cavity, forming a tight seal around irregular objects such as wiring, plumbing, and framing materials, it reduces air infiltration as well as heat loss or gain. As a result, it will provide you with both excellent thermal insulation as well as acoustical insulation. Your house will be more comfortable and quieter.
    As far as water heating, have you considered pairing a solar water heating system with a propane fired on-demand unit as the back-up source? The solar system will provide you with your primary hot water. The on-demand unit would only operate when the solar unit isn’t providing optimum temperatures, e.g. during continuous cloudy or rainy periods.
    A couple of options for cooling (not knowing where you are located): a) you could install a whole house fan — a unit that would be installed in your attic and designed to pull warmer, stale air out of your house, or 2) you could install an evaporative cooler — a system that cools incoming air using chilled water (best suited for climates where the air is hot and humidity is low).

  4. Jeannie

    Dear Mr. Allen,
    I live in a very dry area (Cambria) and we suffer from severe water shortage on an ongoing basis. Yet every winter when it rains, I see tons of water running through our properties and down the road. Is there any way to retain some of this water and utilize it for a property without a well? If not, what does it take to get a small well?

  5. Dennis Allen

    Wouldn’t it be wonderful if every home in Southern California used the sun’s energy to produce all of its electrical and hot water needs? Go Solar!
    Unfortunately, we are not aware of any incentives specifically for low income home owners to install help them install a solar photovoltaic or hot water heating system. However, the state of California currently offers rebates for solar photovoltaic systems and (according to an article on the front page of today’s LA Times’ California section) is currently considering expanding that rebate system to include solar water heating systems. There is also a federal tax credit for solar — up to $2,000.
    In the Santa Barbara area, where we are based, the average cost per kilowatt installed for solar photovoltaics is around $10,000, prior to any rebates and tax credits. The average cost for a solar water heating system is between $4,000 — 6,000.
    The good news is that there are not any regulations that we are aware of that limit how much solar you can have on your roof. And, thanks to state legislation that went into effect in January 2006, local jurisdictions can no longer deny the installation of a solar system based solely for aesthetic reasons. But, there are two physical factors that can limit how much solar you can have on your roof:
    1) How much of your roof space is oriented appropriately for solar (preferably a southern orientation)?
    2) How much additional weight can your roof support? For example: water weighs approximately 8.34 pounds per gallon and, with a 40 gallon storage capacity in some solar hot water systems, that means an additional 334 pounds your roof needs to support. You might need to add some structural support to handle the additional load.
    Look to the California Energy Commission website ( to search for a solar installer that serves your zip code area.

  6. Dale

    Dear Mr. Allen,
    I have a multistory older house with no insulation, no heating or cooling, and lots of windows. On a budget, would blowing in cellulose from Home Depot be my best choice to insulate the walls? Also, for heating and cooling, I was thinking of do-it-yourself solar water heating with copper pipe and the rest of the heating with propane as I can’t get gas. There’s a lot of wind here too, but I have the idea that a windmill is too expensive. I didn’t have any other special ideas for cooling besides maybe a windmill for electricity.
    Thanks, Dale

  7. Dennis Allen

    Jennifer –
    Congratulations on getting rid of your carpet — that’s a big green step towards improving the indoor air quality of your home!
    In answer to your first question, if you are handy and have the proper tools, you can certainly install a new bamboo floor. Prefinished bamboo flooring would be easier for a DIY installer than site finished types. An existing plywood subfloor will make your job easier, since the chances are that the floor is already level and the plywood gives you something to nail your new floor into. However, if you have any concerns about whether the floor is level or the room is square, or if you find that you have a concrete subfloor rather than plywood, I suggest that you rely on an experienced installer to do the work. The odds are that you will be more satisfied with the end result.
    Now for your second question, how do you know if you are purchasing a “green” bamboo floor product? One of bamboo’s greatest benefits is that it is a very fast-growing plant. Its two to six year harvest cycle makes it a rapidly renewable resource, especially when compared to the majority of other wood floor products — oak, pine, maple, etc. — that take decades, even up to a century, to grow. Bamboo is the same as a grass — you cut it and it re-grows from the same root stock. Be sure and get mature bamboo — grown for five to six years — as it is denser and much harder than floors made from two — three year old material. The mature material is extremely durable (a 30-50 year lifetime) and is harder than a red oak or maple floor. However, because the majority of bamboo comes from Southeast Asia, it has significant embodied energy stemming from the associated transportation impacts. And, you raised the point regarding potential ecological damage from the type of practices used to harvest the product.
    Other important things to consider when purchasing new bamboo flooring are: Has the product has been thoroughly kiln dried to avoid warping over time? What is the formaldehyde content of the — has it been made with environmentally and health friendly adhesive materials?
    To determine the “greenness” of a bamboo flooring product, ask your product manufacturer or supplier about these issues and look for the Forestry Stewardship Council (FSC) label, which will ensure that the product has been sustainably harvested. Good sources: EcoTimber, Teragren, or Smith & Fong, Co.

  8. Oscar

    What kind of incentives are out there for low income homeowners to install solar power, or solar water heating?
    What’s the average flat cash cost for the homeowner, and what kind of financing is available for something like that?
    Also, can you have both solar power and solar water heating, or is there a limit to how much you can have on a roof?

  9. Jennifer J.

    Dear Mr. Allen: I am interested in taking the carpeting off the floors in my condo (I think there is plywood underneath), and putting in bamboo flooring. Is this something a do-it-yourselfer like me could do? Also, I heard that some bamboo is not really “green” and comes from countries where ecological damage is done to harvest it. How do you know if you’re getting a green product? Thank you in advance.

Comments are closed.