Strengthening attic floor

Fergus · 2009-11-26 11:19:32

Hi guys.. I know this has come up before, and that there are numerous variables, but as a ballpark.. The house is 3 bed semi circa 1968 and has concrete hollow block exterior and interior walls right up to the attic, i.e. the attic joists span the same concrete walls as the bedroom floors. The main floor appears to be 8x2…

26-11-2009 11:19AM

#1

Fergus

Registered Users, Registered Users 2 Posts: 532 ✭✭✭

Join Date: May 2001

Posts: 491

Hi guys..

I know this has come up before, and that there are numerous variables, but as a ballpark..

The house is 3 bed semi circa 1968 and has concrete hollow block exterior and interior walls right up to the attic, i.e. the attic joists span the same concrete walls as the bedroom floors. The main floor appears to be 8x2 (actual measure 7 x 1.5) at 14 inch o.c., whereas the attic joists are 5x2 (i think, actual measure is 4.5 x 1.5), also at 14 inch o.c. The spans between the centre wall and front/back walls of the house are 12 ft and 14 ft. The roof rafters are supported by two large beams between the attic walls (no trusses).

My question is, can this type of attic conversion be done by just sistering the existing joists, or does it need new beams/RSJ type of thing and new joists etc?

0