"The Henchman" wrote in
:

Tight budget, and I'm a novice diy'er.

My wife wants my to build a wall to wall bookcase that is floor to
ceiling. There will actually be 3 sections because we want the end
sections to have workstation or desks. They will be fastened to the
wall. My wife and her family suggested I make everything out of MDF
which is cheep, easy to treat and easy to by decorative faces and
mouldings for.

However I'd like to seek opinions on how long 5/8" or 3/4" MDF will
last if two adults and two kids use this type of configuration for 20
or 25 years or hopefully 40 years?. What's the life span of MDF for
this type of application? We are in Ontario Canada so air
conditioning 3 months a year and forced air heating for 7 months a
year from a humidity standpoint. Is there plywood that is affordable
and nice to prime and paint and that we can nail some mdf moulds to?
Melamine is prolly out of the question cause of looks and it's really
tough to paint ( it's a home office library, not a kitchen)

This room will be used a lot we think.


My primary considerations for material choice would be weight and
tendency to sag. It seems the composite materials such as MDF or plywood
have a larger tendency to sag than 1x material. In fact, we've got
several book cases built out of 1x12s that show no signs of sagging.
They're also significantly lighter than a plywood or MDF bookcase would
be.

If you still want to use MDF for the shelves, you may consider using a
plywood back. This would allow the shelves to be secured at regular
intervals from behind as well as from the sides, and will reduce the
likelyhood of sagging. You may find it's cheaper to use a piece of 1/8"
hardboard and 1/2" sheathing grade plywood rather than buying better
quality plywood just to paint it. (The hardboard is to provide a smooth
paintable surface. I don't trust its ability to hold screws.)

Puckdropper
--
Never teach your apprentice everything you know.