I will be starting the construction/renovation of an existing 800 sq/ft home in October; it is conventional 2x6 R20 batt construction with 6 mil poly behind the drywall. I will be removing the vinyl siding and existing windows and doors, replacing them with new triple pane units from an un yet determined source (another question I need answered best windows for a reasonable $$).

The plan is to add 6 inches on EPS (up from the 4" I was going to use) to the exterior of the existing structure from footing to roof line as well as to the exterior of the new construction (an additional 800 sq/ft with a walkout basement below (so 2 x 800 really). So R12 + R20 for whole wall about R28 if I've followed along properly.

To the point though...

Home Depot is the only retailer I've located locally that carries 8" screws (1/2 furring strip + 6" EPS plus 1/2 OSB plus 1 1/2" penetration of wood stud) but they are crazy expensive. (I need 8" 1/2)

I'm in Canukistan where the prices of everything is disproportionate high compared to the US. I can and will travel to ND or MN for a better deal already planning on buying EPS in Grand Forks ND (Menards) as its about 50% of the local price.

Is there an on line source for the long screws that won't break the bank. (In my market the longest I can find (8") are $2.00 (plus tax) EACH

I would compare with the price of all-thread with nuts and washers.

I'm not sure I follow how to use threaded rods/washers/nuts...

are you being facetious? Or is that an option I haven't just heard offered before..

Please hold up the sarcasm sign if its not meant seriously

Long screws are not cheap, and can be close to foam cost. I assume you are going to use 3/4" strapping on top of the foam, so the strapping + 6" EPS + 1/2" sheathing = 7-1/4", so you'll need at least 8-1/2". Timberlok has a 9" screw that would work for about .76/each: http://www.mcfeelys.com/Product.aspx?id=727763.

Thanks...at 76c I can afford them...$2.00 is over the top...I imagine everyone applying exterior foam is running into the little surprise.

Cheers

one of the benefits of a Larsen Truss

Bob has a better idea...:-).

Thanks...at 76c I can afford them

You might look at HeadLoks from FastenMaster, the same company that makes the TimberLoks. They have a much larger flat head that might be more suitable for holding the thin furring. They usually require a 2" penetration depth in the stud, so you would be at a 9" screw. They come in 250 screw buckets and you can get them at Amazon.com for $USD0.75 ea in that quantity.

I went to Dekfast screws designed for installing roofing insulation. Available from Bestmaterials.com I think 7" screws were about $150 for a bucket of 500. They are available in 1" increments up to 20"+
These are phillips head screws and to install they I bought a corded impact driver and it worked great.

The dekfast screws at $200 for 500 works out to .40c a screw....MUCH better; thanks.

The Larsen Truss looks like a steep learning curve and several times the work so its out.