Creaking From Joist Hanger

[budest]

Hey guys,

OK so joists are set into hangers using 6 nails (3 per side). I am getting an awful creaking noise like metal on metal from the hangers in several rooms so to experiment I have removed the nails from the noisy hangers in one room and of course the creaking has now stopped.

What is/was causing the nails to make this noise as it seems from my research that joists must be nailed to the hangers?

Now that the nails have been removed could I get away with using a construction adhesive to secure the joists to the hangers or must the nails be put back in?

 

[budest]

Another issue i've been having in my bedroom is creaking coming from the blocking between the joists. Again this is nailed and upon removing the nails in one affected area the creaking reduced significantly.

Fortunately this is only an issue in two isolated areas so not a major job. But what I need to know is if, again, the nails can be replaced with an adhesive? If so is silicone fine or would a 'no more nails' type adhesive be ok?

It's a new build but Housing Association and therefore I'd rather tackle this myself rather than to go through the motions trying to get them to sort it.

 

[tony1851]

Solid blocking is rubbish because as the house dries out, the timber joists shrink slightly in width and a tiny gap opens up between the blocking and the side of the joist. This gap allows relative movement between the joist and the edge of the block, because the nails will bend slightly. The movement causes rubbing, hence the squeak. Try stuffing the gap with some flexible sealer to give some elasticity.

(traditional herringbone strutting was far more effective).

As regards the joist hangers, they should be nailed according to the manufacturer's detail. The nailing is necessary not just to hold the joists in, but also to aid lateral stability. Don't think just adhesive would be OK here.

 

[budest]

Thanks for that mate.

How disastrous would it be to actually remove some of the blocking? I'm talking about say 4 pieces running consecutively between joists.

I think a better question would be, what are the blocks for? Are they supposed to support weight bearing on the joists?

 

[tony1851]

what are the blocks for?

They serve two purposes:

1. To help prevent the joists twisting sideways (particularly with longer and deeper joists); and

2. They help to distribute loads between the joists. Eg if one particular joist was loaded with a heavy piece of furniture, the blocking helps spread some of that load to the two adjacent joists.

When deciding on the size of joists to use, the architects/engineers will have allowed for this load-sharing effect. Not really adviseable to remove them - you might find the floor deflects or bounces just a little more, though it wont collapse!

 

[budest]

Thanks again Tony.

I experimented today with two pieces of blocking numbered 9 & 10 by whoever fitted them. I hit them out from their securing nails and inserted them again using No More Nails to cover the sides and bottoms and left to dry. Now whilst full cure can take up to 24 hrs they have already set and not a single creak from them! I fully appreciate it will take a few weeks and various room temperature adjustments to see if it has fully fixed the issue but I'm quietly confident as with any other "fix" I have implemented I could tell immediately it wasn't 100% whereas this time there isn't a noise. Fingers crossed.

Stands to reason the creaking should be fixed as it was the nails that was were causing the blocks to shift slightly as the boards expanded and contracted with room temperature. I noticed the noise more when the room was cold actually.

Regarding the joist hangers I had/am having serious issues with them as I mentioned earlier. The sound of metal against metal (nail against hanger) is awful. So I replaced the toe nails I had taken out only I left a gap between the nail head and hanger and applied some adhesives to prevent the contact in the future and also some adhesive between joist and hanger. So far so good but at least this way the nails are replaced thus giving me me more piece of mind.

Came across this fantastic document on noisy floors that read like it was written just for me. I advise anyone who is having these issues or wants to know how to resolve them to carry this as your bible:

http://nascor.ca/wp-content/uploads/Prevention-and-Repair-of-Squeaks.pdf