Detail to tie existing masonry wall to existing joists

[bookowski]

I'm trying to work out a simple detail to tie existing masonry walls (front & rear facade) to existing timber joists that are running parallel. This is for 3-4 story brownstone style buildings with timber joists that span side wall to side wall.

The most basic detail is the old star on the exterior with a threaded rod through several joists. Assuming that I can't have anything on the exterior the next option is a similar detail but using an epoxy anchor into the masonry from the inside. Fitting a rod through the joists seems difficult unless the holes are significantly oversized. I am also assuming that the subflooring is remaining so no straps or access from the top of joist.

I've seen a few variations on this but none of them appear very easy to install. Does anyone have anything that they have used successfully?

 

[spats]

Why are you not tying wall-to-wall through all the joists? That's how it's normally done. I can't see just pulling on the joists. You obviously need access from above or below to install the rods. You will need full depth blocking between the joists staggered on either side of the rod to take the compression load.

As you said, the rods are normally anchored by masonry stars on the outside, and all rods are two piece with a turnbuckle for tightening. If you can't use the stars, why not epoxy allthread into the wall, and connect to the turnbuckle. If you don't want to use allthread full length, you could connect the allthread to a rod threaded only at the end using a rod coupler.

 

[bookowski]

Access/constructability seems difficult without going through the wall. I don't think you can get a drill between the joists to provide the hole into the wall. I'm also not sure how you get the rod into the joists - isn't the spacing of the joists going to prevent getting the rod up and in there?

I have not typically gone the full length of the building, I'm not sure this is necessary - this is another issue though. I do provide staggered blocking as you said.

 

[kieran1]

don't know where you are based, but in the
uk i've used this system many times. I guess it depends on how out of plumb the wall is. If it is a large concern I would do as Spats has described

Kieran

 

[bookowski]

Thanks kieran. I'm in the US but I'll take a look, perhaps there is something equivalent here.

The walls are not out of plumb, they are in good shape. The buildings are being renovated and as part of that process we are incorporating ties. The facades are landmarked and we have been asked to avoid penetrating from the exterior. I'm trying to figure out if that is realistic.

 

[hokie66]

You could position the rods at the bottom of the joists rather than through them in order to have room to drill. Blocking between the joists will still provide the compression resistance you need in order to tension the rods.

 

[SAIL3]

If one uses just one epoxy anchor, then it is only activating the shear resistance of the that one block or in the case of brick only the immediate surounding bricks at most.
My understanding of the increased effectiveness of the old star is that it captures a greater area of the wall and utilizes the length of the perimiter of the star to activate more of the wall in shear.

 

[SLTA]

IF the walls are in good shape, why are ties needed? Are the ends of the joists damaged in any way?

 

[bookowski]

These are the front and rear walls, they are not connected to the joists - the joists run parallel to the walls. They are essentially freestanding over the height of the building. This is typical for this age/type of building. Normally we recommend tying the walls back to the floors even if there is no indication of a problem.

There are obviously lots of ways to do this. I was just wondering if anyone had seen or come up with anything easy and clever to avoid touching the exterior.

 

[spats]

Unless the building is prohibitally wide/long, I would still tie all the way across, and there's nothing wrong with stars. Almost any building needing this kind of remediation would be old enough to be a landmark. I used them on an 1897 Jail. They can be quite decorative, and don't distract at all. Maintaining some kind of symmetry is always a plus.

 

[dhengr]

A product like Kieran1 shows is available in the U.S., I’ve seen it used and promoted, but I can’t put a manuf’rs. name on it at the moment. Check with some local masonry products and hardware suppliers they will be able to get them. Read his attachment. You will probably accomplish what you want, which I assume is just add some stability and support points to masonry walls which are otherwise in good condition, by engaging a couple parallel joists. Appropriate blocking btwn. the walls and the involved joists will engage the existing diaphragm action, whatever that is. When done properly these ties are really not very obvious upon completion.

 

[hokie66]

If the building is not too wide, you might consider installing horizontally spanning beams below the joists, connected to the side bearing walls.