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  1. #1
    Join Date
    Sep 2013
    Posts
    2

    Default Electric heat in ceiling; plaster cracks, is there a special product we could use?

    We have a circa 1970s home with electric wires embedded in the ceiling, controlled with zone heating. A few areas had long cracks in the ceiling plaster. We had a fellow who claimed he knew how to work with these ceilings repair the cracks, and they looked great for a few months but the cracks are now back. The main ceiling is made of plaster (not drywall) and he mixed up something to repair the cracks. Is there some type of special hardener or heat-resistant plaster that would make a more durable patch? Taking down big sections is not possible because the wires are thin and cutting any would cause the whole system to malfunction. Any info would be appreciated.

  2. #2
    Join Date
    Jun 2009
    Posts
    271

    Default Re: Electric heat in ceiling; plaster cracks, is there a special product we could use

    Check on this product.
    Master of Plaster.
    It is a true repair plaster product it is a veneer it is the old time real plaster finish.
    you can get a thin mesh tape from them to cover the cracks the total thickness of the repair material will not exceed 1/8 inch and should not effect the heating trough the plaster. This product can be applied over a painted surface.
    Before you do any repairs to this ceiling make sure the cracks are not due to failing attachments that are holding the lath in place or failing structure supports.

  3. #3
    Join Date
    Aug 2007
    Location
    Portland, Oregon, formerly of Chicago
    Posts
    1,611

    Default Re: Electric heat in ceiling; plaster cracks, is there a special product we could use

    I am kind of a pessimist when it comes to heat embedded in the ceiling plaster. The rapid heating and cooling of the plaster with expansion and contraction is just begging for a crack or cracks to develope. How is plaster suppose to releave the stress of movement? Floors are given gaps at the margins so that it can expand without damage. Large drywall ceilings in non-climate controlled areas are often built with expansion joints. There is no provison for expansion in plaster that is being subjected to heat/cooling stress.

  4. #4
    Join Date
    Jun 2009
    Posts
    271

    Default Re: Electric heat in ceiling; plaster cracks, is there a special product we could use

    Plaster ceilings also requires perimeter relief. Some depending on size in Sq / Ft will require engineered control joints which would require back to back supports using a metal joint to serperate the plaster.
    Any rapid change of the heating due to changing the thermostat could cause cracking.If the room temp. is above 55 Deg. heat change will have little effect on the plaster. If the room temp is below 55 deg. the temp. change should be made at 5 deg every 24 hrs. until the 55 deg is reached.A change in temp of 50 deg. could cause a plaster ceiling 100 L / f to expand by 1/2 inch.
    Also note that all ceiling / Wall trim can only be attached to the wall NO ceiling attcahment is allower ceiling must be free to expand perimeter relief min is 1/8 inch.

  5. #5
    Join Date
    Sep 2013
    Posts
    2

    Default Re: Electric heat in ceiling; plaster cracks, is there a special product we could use

    Thank you so much for the information!

    Since we have the ceilings that we have, and the heating system that we have, I guess our best shot is to try the Master Plaster and hope for the best!

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