January 27, 2010
By Zeke Miller, guest blogger
Part 2
Last week I started talking about common specification pitfalls. In this week’s blog I complete my top 10. These are in no particular order, but I have closed with the “All Timer.”
- Using manufacturer’s details – This applies more to drawings than specifications, but please do not download details to use on your drawings from the Alpolic, Alucobond, and Reynobond websites. The details found there are extremely generic in nature. The details should actually come from your regionally based fabricators because some attachment systems are only regionally available. For example, in the Southeast we (the fabricators) do not offer true rout & return dry joint attachment systems. We offer back ventilated rain screen attachment systems
- Specifying 6mm thickness material – There is no real advantage to specifying 6mm over 4mm. You might think that 6mm has to be stronger, but in truth, the aluminum skins are still .020” thickness. The difference in thickness simply comes from a larger polyethylene core. In my opinion, the only thing that 6mm brings to your project is material setup charges, curving limitations, and additional cost.
- Specifying one type of attachment system but drawing another – There are literally too many times to count where we have seen one type of attachment system listed in the specifications, but another type detailed on the drawings. We are then left in the unfortunate position of having to guess the architect’s intent, possibly to our pricing disadvantage.
- Listing air/water infiltration criteria but specifying a rainscreen attachment system – These are mutually exclusive. A rainscreen system, by design, allows water and air infiltration. Listing testing criteria that’s applicable only to sealed joinery systems just confuses everyone.
- Using an editable specification, but NOT EDITING – Once a month or so we will see the ultimate in vagueness. This is when the architect lists a rainscreen and a sealed attachment system, a Fire Retardant core and a Polyethylene core, 6mm and 4mm thickness, standard and custom color, 2-coat (opaque) and 3-coat (metallic) finish. When this occurs, it is simply not possible for the general contractor to conduct an apples-to-apples comparison of subcontractor pricing.