New Joists for Loft

[ziggy1979]

Hi All

Is it possible to "laminate" (with glue and screws) new and bigger joists to existing ceiling joists in order to strenghten the ceiling joists for a loft conversion or are rsjs, etc. absolutely necessary. The rooms above which the loft conversion would go have brick walls and are approx 4 x 3 m.

Thanks.

 

[JerryM]

absolutely necessary - no

the trouble is the ceiling joists usually lie on the longest span where as the rsj's or wood joist's are generally at 90 deg and on the shortest span.

u would need to do some calcs.

given u have brickwalls below then u will be able to use split rsj's with interim support off the walls hence easing installation and sizing.

the other factor is normally to leave a gap between the new joists and the existing ceiling to avoid cracking.