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Plastering & Rendering

why have hairline cracks appeared in plaster after mist coating

Anonymous user 03/03/2024 - 3.19 PM

Hi all - I recently had my daughters bedroom ceiling over boarded & skimmed, and walls skimmmed early August. A few hairline cracks appeared after the plaster dried out, so they was racked and filled. Didn’t get around to applying must coats until this week. Applied 1st coat, left to dry for 18 hours. No big issues but noticed some notches and trowel marks, so filled & sanded. Next day applied a 2nd mist coat, left it to dry almost 24hrs, and have noticed cracks, 1 on the ceiling vertically (was 1 of the cracks that was filled) and 1 on a wall horizontally (new crack).....why would this be? Any guidance would be appreciated.

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5 Answers

Anonymous user

If this is over plasterboarded walls/timber frame could be that plasterboard not correctly fixed back.hence movement and cracking
Answered29 October 2018
2

BG Plastering and Painting and Decorating specialist's

Rating: 4.6 out of 5
Canterbury
The most common cause for hairline cracks is the plaster has dried out too quickly. Other causes could be not scrimming the joins or the plasterboards havnt been secured properly. Use bins zinsser to seal the cracks first and this will solve the problem
Answered20 March 2019
2

Anonymous user

they might not have taped the joints in the plasterboards before skimming which causes cracks were the joints are.
Answered27 October 2018
0

Anonymous user

Hi there , It sounds like some of the tape has either been left off the board joint or fell off during the process and they may of not noticed which could be causing the cracks to keep appearing . In regards to the trowel marks sounds like they will need a little sanding as they may not of had enough moisture on the plaster when they were trowling causing the trowel to skip and leave a mark .
Answered28 October 2018
0

Anonymous user

This problem is commonly caused by these three issues :plasterboard not being fastened to the studs correctly :Scrim tape not fully covering the plaster pad joints : heating the room above 25•c before the plaster has settled :lateral movement between plaster boards positioned too closely together
Answered5 January 2019
0