Re: Hole Diameter for running cable

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Marc_F_Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message

<stuff snipped>

> If you remove that material, you don't increase flexing of the beam.
(This
> assumes a homogeneous material -- no big knots or other weak spots.) So
> scabbed boards that extend two hole diameters to either side of the hole
> should be ample using three screws per side (assuming steel or plywood
that
> the screws  won't cause to split.)

Agreed - but this lumber is low quality with knots and other imperfections
that could easily contribute to an overall weakening of the joist.  I
suppose as every arch has its keystone, every beam has a spot where a given
hole can cause the most structural damage.  Since timber was so precious in
the early years of WWII the wood in these houses is clearly substandard,
something I learned, of course, only after we moved in.  The roof boards
were severely cupped and the roofer said he believed they had not been kiln
dried.  There was no building paper used to underlay the floors and the
walls above weep plaster dust into the basement through the subflooring
joints.

Given that those are the shortcuts I can see, I'm going to brace the vacuum
cleaner pipe holes - and I may only brace the joists where the pipe hole
would run too close to a knot above or below the hole.  I've been trying to
line up "the best shot" for the pipe but a path that avoids all knots in all
joists doesn't seem to exist.

--
Bobby G.