Ceiling Under Attic Problem

[R. Gerard]

We have a heat pump. The compressor is outside; the air handler is inside, in an unfinished attic. I.e., there is no flooring and access is through a "hatch" reached by a ladder.

Every time someone goes up there, to service the air handler, install an attic fan, etc., the heads of nails holding the ceiling to the joists "pop" through the ceiling below, making a very noticeable dimple in the paint, and occasionally breaking through. It's a real drag having this happen every time someone goes up there.

Is there some way to prevent this from happening?

I thought that if I were able to floor part of the attic, i.e., the areas where these servicemen need to walk in order to access the air handler, might this spread the load somewhat and perhaps prevent these dimples from forming every time they go up there?

If so, what thickness of particle board should I put down?

If folks think this won't do the trick, what might???

Many thanks, Bob

[RicodJour]

Particle board is a bad choice - for anything. If it's just a narrow area where they have to walk use planks. Generally using 1/2" ply is all that is needed for such an application, but the 1/2" ply is probably a bit thin to distribute the load. Stiffness is proportional to the thickness of the material. You have to balance that with not adding too much weight - hence the planks. You don't need a high grade of wood at all, and a couple of 1x8s next to each other will form a sufficient walkway. It'll be easier to get planks up there anyway. Don't have adjoining pieces break on the same joist - stagger them. A lower grade cedar might be your best choice, balancing weight, strength and cost. Plus they smell nice.

Pull those offending nails and use screws. They won't pop the same way. Space them about 8" apart - 1.25" is all you need.

R

[Joseph Meehan]

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I like RicodJour's ideas for the floor. I will add another. Try replacing the nails with drywall screws as they pop. You can add one screw on each side of each pop. That should reduce the problem.

[G Henslee]

Not so fast... It seems to be the perfect and recommended tile substrate of choice for Rudy and his 30 neighbors who got stuck, oops I mean blessed with it.

Of course nobody else on the planet accepts it for that, but Rudy says that second only to 3/8 plywood it's the substrate of choice for him and his neighbors.

[Colbyt]

Our house is similar. The builder provided walk boards made from 2X stock. We have never had a problem. I feel pretty sure that if he thought a thinner material would work, he would have used it.

Colbyt

[trader4]

1/2 inch plywood will spread out the load just fine. Those joists must be pretty skimpy, as I've never had this problem occur when walking on joists in any of the homes I've owned. Maybe it's the weight of the air handler plus a person that's pushing the limit and making the joist deflect too much.

[RicodJour]

That's entirely overkill. He probably had the boards lying around and threw them in. If there are any signs of nail holes, paint or cement on them, they were used somewhere else first and then used as your walk boards.

R

[R. Gerard]

Gents! Many thanks to all of you for your input. I would not have thought of approaching the problem from the point of view of either replacing the nails with screws or bracketing the popped nails with screws on either side.

Think I may go ahead with putting some flooring up there anyway just to make it a bit easier for servicemen to get around...and reduce the possibility of one of them putting his foot through my ceiling!

So...planks and not particleboard???

bob

[Evodawg]

It sounds to me like you have a engineering problem with the size of your roof joists. That should not happen. But not much you can do about it now. Sometimes I wonder what city building inspectors really do. Sit on their thumbs obviously. Try the other suggestions with the d/w screws and planks or plywood to evenly distribute the weight.

Rich

[Stretch]

When ever I replace a heat pump with an attic indoor unit, I put in a walkway using 5/8" to 3/4" plywood. Plywood less than 5/8" will not support my fat ass. I go at least 18" wide and prefer 24" wide. The walkway is required by code here, but not enforced well/ I figure it into the price of the job, it is cheaper than replacin a ceiling my foot went through. It is also better than having an employee hurt, even though we have workers comp.

But it sounds to me like you have a problem wthh your trusses. Even if you add flooring, your trusses will not get much stronger, likely your problem will contimue. Perhaps you should twin your joists (add other joists next to your existing joists) and fasten them together with screws. Then put the flooring on top.

Stretch

[Bill Green]

You're so full of shit you fag.

[R. Gerard]

It's interesting to note that when the service men came out to work on the air handler and I pointed this problem out to them, they responded that they see this _all_ the time and that angry homeowners always blame them for it.

They were so happy to find someone who recognized it was not their fault that this happened. bob

[RicodJour]

It kind of is their fault if they don't tell you about it as soon as they stick their head up there. If they know it's going to happen they should warn you beforehand.

R

[R. Gerard]

Good point. bob