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Steam pipe through drywall

Giacomo Member Posts: 1
I am finishing a basement and have been advised to use the steam pipes as the heat source for the basement.  I had the old insullation professionally removed and am now ready to drywall the ceiling.  The main steam pipe runs along the length of the basement and smaller pipes feed the steam from the main pipe to the upper floors.  The smaller pipes will have to run through the ceiling's new drywall.  How do I treat/finish the dry wall.  Do I insullate the pipe to the edge of the drywall surface then tape/compound or is there a trim piece that would finish the point where the pipes goes through the drywall?...


  • kcopp
    kcopp Member Posts: 4,397

    gave you that advise did not understand steam. The supply piping should be insulated fully. The boiler will have to work much harder to heat the upper floors. Leave a small space around the piping. They have trim rings to go around them.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,849
    I second that.

    Bonding your pipes to the drywall is a good way to crack the drywall. I can show you where they did something similar with mortar and block in my basement and the mortar is gradually disintegrating. Steam pipes get hot. They expand and contract. They move around. You'll notice you need to keep sliding those trim rings up against the wall and be glad you didn't try to spackle around them.

    I also agree about insulating those pipes. I wrapped mine in 1 1/2" fiberglass insulation and my basement is still warmer than the rest of the house, but the rest of the house is much warmer and the system is a lot quieter. If you do a better job than I did, you might need to provide more heat, but there's a way to do this without crippling the efficiency of your system.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Jamie Hall
    Jamie Hall Member Posts: 22,972
    and third...

    You must insulate the steam mains, risers, and runouts to the extent possible.  1 inch thickness seems a reasonable thickness.  Otherwise you may run into an assortment of problems, ranging from noise and water hammer to uneven heat upstairs to no heat at all in some areas of the upstairs.  It would be a rare and draughty basement which didn't get enough heat even from the insulated pipes plus the boiler.

    And as hap said, steam pipes move as they heat up and cool down.  Wherever they go through a partition, floor, or beam, they must be free to move; otherwise they will probably make a noise as they expand and, in the case of drywall, they will tear the drywall apart where they touch.  Use proper hangers to support the pipe.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • crash2009
    crash2009 Member Posts: 1,484

    When I first got this place all the insulation had been removed and the drywall and plaster had been applied to around the steam pipes.  The pipes (normally) expand and contract.  This motion eroded the drywall, and plaster to a lesser extent.  This erosion action caused small chunks of drywall to be falling all the time.  It was really messy.  Some of the pipes ran through a bathroom and the drywall dust/chunks were everywhere.

    A couple years ago, I insulated all my steam pipes.  Some good things started to happen.  I saved $750 in fuel the first year.  My steam system runs better and is quieter.  The drywall/plaster erosion problem is gone. 

    If you are planning to heat the basement with the pipes,  ask your heating man How many BTU's you need for each room.  Then remove just enough insulation to match the btu's required.  There is a bare pipe btu loss calculator in this old insulation thread, and also some ideas on how to install the pipe wrap so it looks good. 

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