To start repairing the sagging cushions, you first need to unzip the cushion covers. In case, your sofa cover does not have a zipper, you can open a small area using scissors.
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If you find the foam completely damaged, just replace it with a new one. Foam for Sofa cushions is readily available in the market and you will not have any trouble in finding good quality foam. After you have placed the foam in the cushion, zip it back or sew it.
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If you find that the base and the foundation of the sofa need to be repaired, flip it and place it sideways. If you see the springs popping out or the base is broken, you should consider repairing it completely.
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Buy plywood, which should be equal to the size of the bottom of the sofa. Nail it at the bottom of the sofa, as it will stop the springs to come out. In the meantime, it will also strengthen and increase the life of the sofa. You should also make sure that the plywood is not visible when you place the sofa upside up. If you see the base visible, cut down the extra piece that is coming out of the front.
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Now measure the other broken parts of the frame. Make sure you measure them correctly, including the thickness, width and the length of the broken part. You can use measuring tape for this purpose. Replace the broken part with plywood, as it is cost effective and easily available in the market.
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Now replace the broken parts, by nailing the new piece of plywood into the affected area of the sofa. If you find it difficult to remove the damaged parts, you can nail a thin piece to reinforce it.
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