Extension, concrete or steel

[cremeegg]

I am hoping to build an extension as soon as I can afford it. An L shape box running along the existing rear wall and one end going away from the house.

If it is attached to the existing house about 45 sqm of block work would be needed.

My question is what are the practicalities of building a steel box instead and filling with insulation and coating that with say timber. Is it likely to cost more or less, are there any other advantages/disadvantages.

Thanks for any suggestions.

 

[kceire]

Steel structure will need more engineered design and certification than traditional block work. May be quicker, but you need someone to do the u-value calcs to ensure minimum part L regulations are been met.

It’s very possible though. Cost wise, probably not a lot in the difference considering you will need additional supports for windows etc