Archive for July 29th, 2010

Working on the Roof

Thursday, July 29th, 2010

We’re now focusing on completing the roof. 

Several items need to be constructed so we can put the membrane on the roof, including the perimeter fascia, the skylight curbs, and the infrastructure to support our photovoltaic solar panel installation (mounts and conduit).  After these items are completed, we can put down the tapered insulation, put in the remaining roof penetrations (plumbing and dryer vents), and then put down the white roof membrane.

Building the Skylight Curbs

The skylights need to be raised off the roof deck and be mounted on curbs.  The curbs need to be above the roof deck by the amount of the tapered insulation and an additional six to eight inches.  Also, to reduce the solar gain and to allow water to drain, we are sloping the skylights to the East.  This slope will provide some solar gain when we need it in the morning, and reduce the solar gain in the afternoon.

Importantly, the curbs need to be insulated.  We have an R-47 SIP roof so installing uninsulated curbs would allow energy to move into and out of our house.  Thus, we are putting two layers of rigid foam around each of the skylight curbs (R-20 with no thermal bridging).

Solar Panel Mounting Infrastructure

Since we have SIPs and there are very few flush beams inside the flat SIP roof, we had custom mounting infrastructure manufactured for our photovoltaic solar panels.  We wanted to limit the number of penetrations of the roof inside the thermal envelope while, at the same time, providing a rock-solid mounting system that could withstand high wind loads.

Accordingly, we had Larson Steel manufacture our solar panel mounts for the SIP roof.  Akeena Solar would then have their racks attached to these mounts.  Pete Larson dropped off the mounting brackets last night. 

Akeena Solar is now on the critical path for our roof membrane installation.

Trenching for San Jose Water Company

Our water meter is in the public right of way in front of our house.  We are responsible for the trenching from the water meter to our house.  With PG&E’s restrictions on keeping at least three (3) feet of separation from water pipes, we need to have a new trench dug from the water meter to the house.  

Ugh …

Opening for skylight increased to 2 ft by 3 ft.  The larger skylights will provide additional daylight inside the bathrooms, which will reduce the amount of electricity required for lighting.

Opening for skylight increased to 2 ft by 3 ft. The larger skylights will provide additional daylight inside the bathrooms, which will reduce the amount of electricity required for lighting.

This is the first part of the skylight curb.  Note the Simpson brackets to fasten the curbs to the SIPs.

This is the first part of the skylight curb. Note the Simpson brackets to fasten the curbs to the SIPs.

The curb construction in progress.

The curb construction in progress.

Completed skylight curb in background; uninsulated skylight curb in foreground.

Completed skylight curb in background; uninsulated skylight curb in foreground.

Custom mounting bracket for solar photovoltaic panel array frames.  These mounting brackets will be used for both the flat and gable SIP roofs.

Custom mounting bracket for solar photovoltaic panel array frames. These mounting brackets will be used for both the flat and gable SIP roofs.

Original underground utilities coming from the street.  Note the water, natural gas, electric (three direct burial cables) and telephone were all in a single common trench.

Original underground utilities coming from the street. Note the water, natural gas, electric (three direct burial cables) and telephone were all in a single common trench.

We need to trench from the water meter to our house.  This trench must be at least three (3) feet from the natural gas and electrical conduit.

We need to trench from the water meter to our house. This trench must be at least three (3) feet from the natural gas and electrical conduit.