Replies

1. 
   DanH | May 09, 2019 09:09pm | #1

   What are they screwed into? Generally if you keep the board from bulging up (ie, put a knee on it) then the screw will be forced to come out.

2. 
   user-7131735 | May 10, 2019 04:43am | #2

   Jhum, if you possess a curious notion, or a strong enough determined desire, you might try a variation on a trick we have used on log homes, timber frames, and Heritage Home restoration alike. These somewhat specialized segments of the building crafts can generate mind bending conundrums, and many entertaining lunch/coffee breaks over the plans desk, that include anecdotes (and much arm-wave engineering) dealing with the R & R demanded from us by two hundred years plus history of innovative craftsmanship (and creative deviltry) involving connectors of infinite and innovative design, joining complex structural members in critical positions. If you have friends (relatives will do if they also happen to be friendly) with experience in these crafts, they could be a resource for you, with infinite tricks learned by "boots on planks" professionalism. This simple trick comes from typical "countersink and plug" technique and tools, but with slight modifications. Obtain, or fabricate, a plug cutter or hole saw the ID of the deck screws OD. A 5/16" (+/-) carbide tipped hole saw with the pilot drill bit removed and arbor shaft in place should be able to carve out a nice, but tight, slight circular recess around the screwhead allowing a grip on that screwhead with various devices. You may first want to try just hand removal with appropriate bit and driver. LOW pressure on head WITHOUT imact could help to allow threads to catch and withdraw. Note that some composite deck screws have a few reverse threads below the drive head that might influence withdrawal as much as the swollen over riding plank material that could be holding it down into the joist fibers, especially if, as suspected here, the screws are not self tappers. That of course makes them Just "threaded nails" pounded in with an impact driver, giving little, if any, thread removal lift and leverage without a #17 cutting point carving the way. The screw equivalent of a double hot dipped galvanized ardox spiral nail. (drives in easy enough, but often brutal to pull with just a hammer) You may be able to insert the flat V-notch end of a simple pry bar into the screw threads between the deck plank and the joist as a pry assist to create extra lift and help the threads catch. Even if only enough head comes up above the deck board level to allow grabbing or catching with another pry tool. We have about twenty different pry/grab demo tools, as you may as well have available. The one I might try first would be an antique reverse impact-hammer pry bar combo that is a life saver in restoration work where the heritage fasteners often are salvaged with care. This tool, as all good solutions, requires care in use when it is important to also not destroy the wood surface the fastener is lodged within, so use a 1/8" steel plate under any pry tool as dent and gouge protection. Get into it and try what seems possible and be open minded to what you are doing. Thinking, and actually using tools in challenging situations will speak to you. Action, effort, tools, and knowledge equal success. Luck helps also.

3. 
   junkhound | May 10, 2019 05:52am | #3

   4x4 and hydraulic jack under deck boards, then screw out.

4. 
   sawdust_steve | May 10, 2019 08:01am | #4

   What exactly is a "reverse impact-hammer pry bar combo" ?

5. 
   Norman | May 10, 2019 11:53am | #5

   Can you get the edge of a beater chisel under the screw head?

6. 
   jahummer | May 10, 2019 12:17pm | #6

   Thanks for the responses. To be clear, I am not doing demo. We simply did not like all the screw heads sticking up. We already removed all the screws that did not spin, and I put in new screws slightly longer and with a much smaller head that did countersink itself into the boards. But we are left with a huge number of screws that just spin, I suspect they just stripped on original install when attempting to run the big pan head flush into the very dense boards. And no the original screws do not have the reverse threads at the top-a full inch of smooth shank, so they are not hung up on the deck boards.

   Was not looking to drill hundreds of 7/16" holes in the deck boards, I saw that trick, wanted to put the new screws back in the same locations so that would not seem to work; again, not doing demo. Even so, careful turning by hand with almost no pressure (the slots are intact) they just spin. Also, climbing under the deck to pry the boards is not going to work, for multiple reasons.

   I am thinking the only recourse is to get a small pry bar and do a little custom grinding on the flat end, get a flatter and sharper profile as well as maybe a semi-circle notch instead of the usual v notch so each side can fit closer under the pan heads. Then assault them carefully to minimize surface damage. I think the whole deck and frame is good for another 10 years at least, so really want to avoid messing it up.

7. 
   Mike_Mahan | May 10, 2019 02:21pm | #7

   If they truly stripped out of the joists and have smooth shanks through the decking, you could try driving them in with a palm nailer and a punch.