Depending on the type of surround Hob Grates are fitted differently for example: - if fitted in a wooden surround it is necessary to add a non-combustible slip (slate stone, etc) in order to protect the wood from the heat of the fire. If the surround is made of non-combustible material (marble) the slip is not necessary, however is sometimes used to make the opening the correct size for the hob.
An advantage of having a hob grate is that you can have a one-piece hearth even for solid fuel, as the fire is high up and far away from the hearth.
A downside is that you need a large class1 flue as the aperture of the fire is quite large and without it the fire may not draw.
If you are considering a hob grate I hope this page assists you with your decision. Personally I think hob grates are some of the most attractive looking fireplaces available.
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