# Forum Home Renovation Sub Flooring  what size steel bearer to replace wooden bearer

## jasper

i am removing the 2 supporting steel posts under my house to give more space.What size steel bearer or pfc do i need to span the 8m that is currently supported by the 2 steel posts and a 230 x 75 wooden bearer.

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## ThePope

You'll need a structural engineer to work out what you'll need, size depends entirely on what load it's supporting. If there's bracing being removed between your steel posts aswell, let the engineer know.

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## jimc

The onestell website has a great engineering span table guide. Just calculate the roof/floor area and it will give you appropriate size beams that will suffice. My advice is once you have an idea of size, you can get approx costing of steel. 
Although get it engineered, not onyl do you need the beam, you need strong enough supports to transfer load to the ground.

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## bigdazza

> i am removing the 2 supporting steel posts under my house to give more space.What size steel bearer or pfc do i need to span the 8m that is currently supported by the 2 steel posts and a 230 x 75 wooden bearer.

  I am a structural engineer. I can tell you roughly what size bearer you will need (250 or 300PFC based on experience) however you will need plans and structural certification to do the job legally. It will probably require an inspection as well. Send me a private message if you need help.

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## econ

im not a structural engineer but a clearspan of 8 metres  will require a substantial beam regardless of the material its made of if it has to support a dynamic load eg people walking , jumping ,dancing on the floor its supporting.
strongly support the idea to seek engineers advice  as dazza has suggested

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## econ

heres a link to onesteel  booklet for residential spantableshttp://www.onesteel.com/systems.asp?systemID=62

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