FREE Shipping on all orders - click for Home Page
|
|
FREE Shipping on all orders - click for Home Page
|
home page » passive solar design chapter » HTM roof detail page ... you are here
A lot of attention has been given to our HTM (high thermal mass) passive solar house plan choice of log roof beams ("purlins"). Please note that you can use dimensional lumber in your roof details if you'd like. Square timbers are easier to build with than trying to use round logs. The main advantages to log purlins are in their availability (you may have to drop trees to create your home site) and their cost (raw logs are usually cheaper and always environmentally better than processed lumber). But what you notice after the home is finished is the way the round logs greatly soften the angular nature of an HTM. They truly add a great deal of beauty to the final product and are a natural choice for a flat roof deck. I think you’ll agree that they are worth the effort in the long run.
There is no "one best way" to build any structure in any one climate and/or soil zone. As with any design question, the answers vary from project to project and need to be addressed in a more holistic manner to function properly. Suggesting alternative ways to create your roof, like those pictured above, is part of our consultation service, as is a floorplan and help with site layout. We just don't provide any custom blueprinting or engineering services. As your consultant, our job is to create a custom design to fit your lifestyle through a holistic approach while saving you more money on the project than you spend on our services. On a project the size and duration of a custom home, saving money is a very easy goal.
You can build your own roof panels (as shown below) sandwiching EPS blueboard atop the ceiling planks. Or, you can order the SIPS panels ready made - it all boils down to cost versus time savings. Insulated structural roof panels ("SIPS") are a great way to save time during construction. Get a quote on vented SIPS panels locally to compare - sometimes the quality is good and the engineering very helpful. Look for R30 minimum and extruded EPS blueboard, not white Styrofoam® bead board, if possible (it absorbs water more readily).
SIPS panels come with faux finishes on the ceiling side, sometimes perfectly imitating tongue & groove or stucco. Always go with the cold vented roof option. "Cold roofs" are a design that will cut your cooling bills dramatically by allowing heated air to vent out the peak. Using a layer of Mylar® "reflectix" atop the felt in a cold roof design is a recommended in a vented roof design. This Mylar layer gives your roof the advantage of reflecting heat back up and not absorbing into the insulation underneath.
|
We'll work with you to create any type of roof you wish, but we have found this system to have a great many benefits. The beauty is hard to argue with. With so much stone, block, and stucco, the use of wood on the ceiling to soften the look is imperative. This choice of material is also more natural and healthier than drywall. Drywall ceilings are so very sterile and, well, just so very white. Think twice before you commit to that type of construction. |
|
Our consultation concentrates on simplicity and ease of construction for the homeowner-builder. Deck roofs fit this need to a T. As you can see in these photos, construction simply consists of building a box and filling it with EPS foam sheets. There are several design details not shown here (like the moisture barrier between the foam and the decking), but the basics are evident. You can see where attention is given to overlapping joints and caulking gaps. Please also note that this is a vented, "cold roof" design with the plywood sheeting laid upon the 2 by 4 sleepers atop the final layer of foam. This allows the roof to vent, preventing overheating and ice dams. Vented, cold roofs are very important in both hot and cold climates. You just can't afford to allow heat buildup in your roof to penetrate into the home. Always design with a vented, cold roof.
As with any aspect of building, there are dozens of ways to approach the construction. The following two sketches are two of the most common methods to construct a cold, vented roof. Pre-built insulated roofing panels are certainly another option - the extra expense is sometimes worth the savings in labor.
For most clients, the "sandwich" style at right is easier to construct with minimal skills. The conventional joist approach shown above is often more popular with contractors who wish to use fiberglass batting insulation. |
|
The ceiling planking shown below is classic penny pinching. As the 2by6 tongue and groove ceiling planks neared the peak of roof, we ran out. The last 10 T&G boards are actually 2by12 planks we notched to mock the look of T&G grooves. Give it a close look and you will see the change in planking material about half way up. Curiously enough, the tongue and groove does not add strength to the deck - it just keeps the boards from wanking as they dry. If you use well seasoned 2by12 lumber, you can plane 45 degrees off both sides of the plank and router Vee cut the middle for much the same structural and visual effect, at a pretty healthy savings.
With any home roof design, it is key to note:
Metal roofing has its strong points, but there are problems.
It is attached with screws. When you nail through bitumen underlayment (Grace), it seals around the spike.
When you screw through it, though, the boring action of the screw causes it not to seal around the threads.
Metal roofs also tend to expand and contract. You will be up there with a screw gun tightening them every 3 or 4 years unless you install a standing seam design, which is expensive.
Eventually the screws will not tighten as they have eaten out the hole and you will have to install all new, fatter screws.
Another detraction is that the color will fade on all but the most expensive metal roofs. They use high grade automobile paint on one brand. Another will actually change color as you walk around it (looking from different sun angles). Others are designed to rust up to a point and then they stop - nice look.
Metal roofs are not fireproof. For the same cost as mid-price standing seam (hidden fasteners), you can get the best shingles which in practice are much more "fireproof". You could start a campfire on a 540# shingle roof and it will eventually burn a hole through the roof and fall inside, maybe going out or at least being easier to fight.
Start the same campfire on a metal roof and it will heat the metal, eventually flash firing the entire roof.
|
Please use your browser's 'BACK' button
|
Hot links to our main website chapters:
|Passive Solar Design|
|Shade Cloth|
|Gas Refrigerators|
|Stainless Steel Appliances|
|Solar Products|
|Septic Systems|
|Composting Toilets|
|Greywater Recycling|
|Drywell Kits|
|Site Map|
|
$95* initial design consultation
Whether regarding HTMs specifically or passive solar in general, our initial consultation will address your concerns.
After reviewing the material, we encourage you to drop us an email with your questions.
|
First, we email an extended outline of tips, tricks, and technical details, many not found on the website.
Then, we ship you a two inch binder jam-packed with the following printed information:
|
|
$9* DVD only
One hour long video on universal DVD format |
|
First half hour walks you through the sustainable design, HTM passive solar earthhome featured on our website. While not a How-To video, the second half does include detailed Infiltrator chamber leach field septic system installation and Sun-Mar composting toilet footage. |
|
Who's TheNaturalHome.com?
|
Phone: 800-563-9720
|
|
PRIVACY STATEMENT - We will never release your name, contact information or purchase history to anyone!
The use of this internet site and purchase of Architerra Enterprises, Inc. (d.b.a. TheNaturalHome.com) products and services are governed by this Terms of Service Agreement and Disclaimer.
By using this internet site, you acknowledge that you have read this Terms of Service Agreement and Disclaimer and that you accept and will be bound by the terms thereof.
Copyright © 1998 - 2007 by Architerra Enterprises, Inc. All rights are reserved, please.