You can buy more shares in your home any time after you become the owner. This is known as staircasing.
The cost of your new share will depend on how much your home is worth when you want to buy the share. If property prices in your area have gone up, you’ll pay more than for your first share. If your home has dropped in value, your new share will be cheaper.
The housing association will get the property valued and let you know the cost of your new share. You’ll have to pay the valuer’s fee.