[Greenbuilding] [BULK] Perimeter insulation (again)

[Lawrence Lile]

Thanks!

> about 1/3 of
total heat loss occurs through the slab edge. It made me begin to think
of the slab edge as a long, thin window.

Yow!

>1. If you have termite shields, why not leave the foam in place year
round?


I don't trust the termite shields.  The bare concrete is designed to allow inspection.  THey will make mud tunnels (the little vampires hate the sun) across exposed concrete, and you can see them and detstroy them.  


>2. How did you ensure that the termite shield made a good seal against
the foundation? This can be a problem because it's hard to get a smooth
finish around anchor bolts.


This is a major problem with termite shields.  The best shields are made of copper, soldered together at the joints.  Mine are made of galvanized steel, overlapped, mopped down with tar, and mopped together with tar at the joints. Not the best design, but affordable compared to copper.  Then we took a caulking gun of roofing tar, and caulked the edge between the termite chield and the concrete. 

 

Indoors, the shield extends under the full width of the bottom plate, then under the sheetrock, then up 1" along the inside surface of the sheetrock wall, under the base trim.  Presumably they'll have to come out where you can see them before getting back into the parts of the wall you can't see.  

 


3. What air and ground temperatures make termites dormant?

50F, according to several sources I googled.  Of course, that could change if your house is heating the ground.  But termites tend to swarm and start moving around int he spring, even if they don't go dormant, they are more active.  That's when they are looking for new colonies, new territory.  Springtime is the time to start inspecting for tunnels along the termite gap.  

I don't know if I mentioned the sand barrier either.  There are certain sizes of sand that they can't physically tunnel through.  This is recognized as a standard control mechanism in Hawaii, which has monster termite problems and never gets cold so they are active 24/7/365.  But the special sand is expensive.  I put a 1 foot thick layer of river sand, 36" around the perimter of the house.  It's not perfect, but easily replaced witht he good stuff if I ever see an infestation, and may have some effect. I like the look of it, planted some native cactus in it  That area will not be mulched with anything that termites like to eat. A common mistake is to add a big layer if bark mulch or wood chips right against the house, "heeeere, termite termite termite!"  

Construction trash, especially wood trash, should be picked up and not buried under the concrete pad like often happens.  

Drainage is the last measure.  Termites love moisture.  Every side of the house should slope away, the house should have good gutters, and the gutter water should be directed away from the house (hopefully to be harvested and used for watering the garden!) 

It's not that I am super paranoid about termites, I just wanted to make sure that I could deal with them without pesticides if I ever get an infestation, which is common in my area.  

--Lawrence