Mike wrote:
We live in the Boston area. We bought our current house a year ago. The
attic is finished with heat. This past winder, all the water pipes to
the attic's bathroom got frozen on a very cold day. We had some
temporary solutions so that the pipes didn't freeze again.

Now I am trying to find a perminant solution. I opened the attic
bedroom's wall and found that the water pipes laying on the floor of
the unheated trangular area behind the wall. Because of the ventilation
required, I guess the area where pipes are can get very cold. Currently
there are some tapes wrapped around the pipes but not completely.

I am thinking of buying more tapes and wrap the pipes more carefully
and tightly. Also, put some extra insulation on top of the pipes. Is
this enough? Last winder the lowest temp was -10F here.

If not, what's a good solution of the problem.

Thanks,

-Mike

Don't just put insulation on top of the pipes, you need to leave the
pipes exposed to the heated space to keep them from freezing.

What I did in our finished attic was to put the pipes inside the knee
wall and then add a second set of studs in the knee wall directly
behind the existing studs, basically a wall as thick as two 2x4s. I
put insulation in the outer section of 2x4s, with the pipes between the
insulation and the heated space, and the insulation is the barrier
between the pipes and the unheated "exterior" triangular space behind
the knee wall.

Ken