I've read that upvc bifold doors end up warping and giving problems especially when they are in direct sunlight. Our extension plans specify upvc bifolds but am wondering if that will be a mistake? Is aluminium worth the extra?
They went the first summer, which is why I think it might have been a faulty batch. The manufacturer has been out and restored the top coat, but it went the next summer. I don't think its normal. Sorry, should have said that initially.