Sunday, November 1, 2015

My Best Truss Attic, 2012

At end-October, 2015, add to blog examples of truss attics, as found by Label: Truss Attic Insulation . It is time I included one completed in April, 2012, then and now considered my "best." It is important because the truss arrangement is very common. I had chances to improve, in each new effort with this truss arrangement. 

One improvement to "best" is in location of the access by dropdown ladder. It is safer to enter an attic beyond confines of a hallway that is on house centerline. The ladder is then less a hole to step into. Here the ladder drops into the kitchen. 

Functional detail in a ceiling, is beauty.

View in the attic, ladder stowed, seen where there is other access from the garage. A Calvert ladder door may be latched or unlatched from the attic, but a helper would be needed to manage folding steps.

A handle at the ladder door and four hand grips here best serve a right-handed person, carrying a burden by left hand. The structure handedness could be reversed.

Preparation included raising the floor for 10" insulation depth, R38, by composite beam method. I must cope with found mineral wool insulation.

R38 insulation is thicker than the space under flooring, but air tightness of the compressing plywood flooring is such that decked areas do not have diminished R value.

A custom HVAC return header will be insulated and covered by decking, a much-reduced obstacle to access.

Two excellent Panasonic FV08VQ5 fans are ducted through-roof in solid steel piping. An adjacent wet wall was open to the attic and was frigid in Winter. The wall is now thoroughly air-sealed.

Before the improvement, the home owners fought mud wasps with traps needing regular maintenance. They will find the maintenance if still needed, much safer now. An attic is not a trash heap in which danger must be accepted. A truss attic is much better insulated with batts carefully,  thickly and tightly placed out to outside walls, than by blown loose-fill.

Please see an alternative and fuller presentation of details, in the supporting Picasa Web Album . An interested person will do better to view the full job photo album at Google Docs .

Many things evolve, and for the better in three years of my construction practice and in the availability of materials from creative suppliers. And, I find cause to comment on things that have not improved. Here are some observations three years down the road:

I have wanted to remark about the bath fan ducts photo above. The uninsulated but efficient solid bath fan ducts do work in balmy Portland, Oregon, where reasonably short. Some condensation might run from the left-most fan of the master bathroom in Winter cold, even if an insulating sleeve is pulled on. I would now ask a home owner to allow two roof penetrations, with much-shorter ducts. Know that I did do good here. The LH fan dumped to the attic. The RH bathroom had no fan. The house survived all of this with growing-up children. The house has sold, and I want new owners to be aware of my achievements and my reservations, via this blog post.

  • Fuller albums remark about wasp traps hanging in view in the above photo. There are reasons home owners regularly navigate their attics, and they and their ceilings are at risk in darkness without flooring. Please appreciate many virtues in my examples of better attics with good access, fixed lights and safe flooring, beyond the durability of insulation, that must be installed to function undiminished, for at least sixty years .
  • Good attic ladders by Calvert USA and Fakro are evolving rapidly despite their difficult availability and our tolerance of junk, in USA. Please check out what is now available.
  • This job was a very good demonstration of my attic floor sealing methods employing GP Densarmor drywall and my flexible grout . This post is an important addition to results of blog search, Label: Attic Floor Sealing . The post is important where in territory of Bonneville Power Administration, and perhaps everywhere, floor sealing is rarely included in weatherization, a grave misunderstanding. Here a long bathrooms wet wall was frigid in Winter, well-connected to attic conditions through large wall header gaps. A frigid, condensing, bathroom wall leads to sure health and home maintenance problems.


kevin d said...


I absolutely love your work and think that your attention to detail, creativity, and diligence in the work that you do is brilliant. I am following your method, and have thus far installed an intelligently placed light switch next to the attic access and led lighting to see what I am doing. Next step is a set of Calvert stairs for safer access. The ultimate goal is proper air sealing, insulation, hardcover, etc. One question I do have for you is that in my internet research I find lots of talk about not adding any load to the bottom chord of a truss roof system. However, looking at the many jobs you have done it appears that you add load in the form of flooring supports attached to the bottom chord and plywood hardcovering, without any problem. Do you have any thoughts or rules of thumb on the issue of loading truss chords? Thanks for all the great info. Kevin

Phil Norman said...


This post and others with the associated Labels, explain and defend what I do. But, it doesn't seem enough to say that. Please see a humility check here:

You might agree the home inspectors lecturing or insulting me, were mean. Please take the bother to sign up and log in, then seeing photos. Inspection News is an excellent learning resource. Then, see that the "box beam" I built in my crawl space, and shared, is a far better solution for the original poster, than ripping out and replacing beams, pulling away from flooring nails. I am delinquent in having my beam method tested at my college, Oregon State University, where I did learn some structural engineering. I let my PE license lapse in an unassociated career. This conversation might be part of a further pitch to Construction and Civil Engineering faculty at Oregon State.