Sistering a joist that is a full 2x8 size

[dhollister]

Hello... Does anyone have experience sistering a joist that is full dimension lumber? I am sistering a joist that is truly 2x8 in a 110 year old home. This is to fix some springiness in the floor above. The question is that since I will be using a 2x8 that is really approx. 1 3/4x 7 1/4, should I put the top of the new board to the top of the floor above, or keep it flush at the bottom. Some additional details on the sistering: the new 2x8 will span the full length of the existing one, and will be supported by a wall on one side and attached to an existing beam via a new joist hanger on the other.

Any insight with this will be ver much appreciated.
thanks!
-dave

 

[Deluks]

I'd fit the new one flush with the bottom, it's there to stiffen the joist, not support the 'whateversupstairs' Plus that way it will get a good bearing.

Use half inch bolts with toothed timber connectors and bolts through every 12".

Fix any noggins on the 'older joist side' first, that way you only have to neil through 2" of timber instead of 4.

 

[dhollister]

thanks for the help... makes perfect sense. What do you mean by 'noggins'?
thanks.

 

[Deluks]

thanks for the help... makes perfect sense. What do you mean by 'noggins'?
thanks.

Dwangs to you, we call them noggins. Or use herringbone struts.