Advice needed -- roofing plywood


First time poster, was looking for a bit of advice if possible. I have been helping my mom get bids on a new roof for her 50’s era house. It is a basic ranch with a single gable roof down the middle.

She just moved in last fall and we’ve discovered over the winter when there are mid to heavy winds, sometimes there will be some creaking sounds from roof. Not all the time, but we hear it occasionally.

When getting bids, due to it having two previous layers, it will have to be taken down to the original wood which is shiplap not plywood. Also, we were given options to lay down 1/2" plywood over the shiplap. My questions are:

  1. Would the extra plywood layer help to lessen the squeaking when it is windy?

  2. Also, some bids mentioned they could keep the shiplap and only replace with plywood if damaged or worn. Since she is on a limited budget, could the whole layer of plywood be bypassed and have them maybe re-nail the existing shiplap with a nailgun into the rafters to reinforce before laying the shingles? Could this also lessen the noises without spending the extra ~$1800 for a full layer of plywood?

Sorry for the long post, was just wondering if #2 could be done to lessen the noise while keeping the costs down?
Thanks for any advice,


I would replace only that which is rotted.Have the roof stripped down to the decking,replace busted warped and rotted decking.I have heard of people stacking plywood directly over the 1x’s but have not tried that since I have never had a customer consider or mention it.I am not a big fan of adding more weight to a roof deck.

As far as the squeaking do you have turbines on your roof? I have had calls about squeaks in attics and have found these to be the culprits.

1.) Turbines
2.) Loose soffits
3.) Weather vanes
4.) Attic vents
5.) Gable vents
6.) Tree branches scraping against soffit,gutters,fascia wrap and satellites
7.) T.V antennas

Anything the wind can grap or move then its a possibility for squeaks. If your roof has 2 layers I really doubt the wind can move your roof enough to cause a squeak.Hurricanes,straight line winds and tornados cause roofs to move.

Do you have any evidence to back up this accusation :?:


Do you have any evidence to back up this accusation :?:[/quote]

Well to make your roof move enough to cause squeaking IMO would need some substantial amount of wind.It is understandable for a multi story steep pitched roof,but the OP stated a ranch.

And yes your roof is constantly moving from earth movement and vibrations and settling.It would determine the type of squeak.

Maybe the OP could describe in detail the sound of the squeak,Hahahaha

IMO…I would pay the cost of adding an extra layer of plywood.

You will have smooth new deck and all nails WILL penetrate the decking as opposed to the existing decking you have. Every board will have a gap that may allow a new nail to be placed in it (will cause a reduction in shingle strength)

And with those gaps…may cause your felt to warp and push the shingle up (elongated bubble)

squeeking… ??? :expressionless:

we’ve laid 1/2" ply over shiplap all the time, does not cause no problems unless your house was made of toothpicks, we put metal drip over all edges when we do it this way, if it was my job i would recomend ply over the shiplap, it will strenghten it and smooth it out…JMO…

Thanks for the replies. To clarify, it’s not really a squeaking sound as more of a general creaking which sound to be coming from the rafters. It’s not a major or frequent sound, but was just wondering if we could just have the roofers re-nail the good existing shiplap to the rafters before laying down the shingles to help lessen this noise – or will we need a layer of plywood to lessen the noise.


even if it doesnt stop the “squeek” they should be re nailing shiplap before applying shingles anyways…replacing any ruined ones.

Ship lap is the best and strongest it gets. DO NOT add more weight the roof was not designed for it. Repair what wood is bad and call it a day. Sqeeks i normally see are from aluminum vents even the can style if the rivet has failed. The guy wanting to add plywood is just trying to add cost. Been at this a few 20 years so i will say for the new guys i started from the ground picking up debris and worked my way to the top. Seen everything under the sun wrong and people ripped off. Have not seen everything yet nor will i since it is a ever changing world but i will say adding more weight will have an effect to the plaster on the home since homes of that era normally have plaster and when you add weight to 2 x 4 walls you have issues when doubling the wood. There is cause and effect to everything we all do and adding more weight is not a good idea.

i disagree with ya gtp i’ve been doing it this way for 31yrs now and have never had a problem we usaully put 3/8’s on shiplap and 1/2" on strapping, no problems…

I am with kage on this one. Re-decking old 1x is the way to go. It will smooth out the roof, and ensure that the nails in the shingles are all hitting wood.
As far as the weight issue goes, think about it like this. A square of shingles weighs roughly 240 lbs. A square of 3/8 or half inch plywood is less than half of that. Your house has 2 layers of shingles on it now, and it has not caved in. It is no problem.

are there collar ties on the rafters (which help hold the roof from dipping and can strengthen the house from winds which push against the wall). They are cross braces made of a 2x material bolted horizontally from rafter to rafter which makes the shape of a capital A. Is the shiplap tounge & groove? If so ask to re nail (at your extra expense) & replace as needed.

if the roof needs to be re-decked, i would suggest 7/16 osb over the solid sheeting be sure they nail into roof rafters. cut out any warped wood and rotten wood especially on eaves.
i would use an eight penny nail to install the osb. the result would be a new clean roof deck.
also check your rafters, you might need to add additional webbing, and collars if your rafters have been fly raftered vs. manufactured trusses.