Double door in a supporting wall

Need a bit of advice about some double doors that I'm hoping to have put into a supporting wall...

The wall currently has a single door that I intend to extend. I've had a qualified carpenter (came recommended) out - he suggested that since it's a supporting wall he could (and I'm not quoting exactly here!) extend the support above the door by putting a 4x9 on its side. He said this is how a timber framed house is constructed...

Does anyone with experience think that this is sufficent to maintain support??? I only ask as I am completely clueless about this!!

Is your house timber framed? If it is then go with what the carpenter says; if it isn't then you need a lintol or an RSJ over the opening.

you probably don't know so: a lintol is a beam made of concrete and steel bars running through it as a support and a RSJ is a rolled steel joist. They come in varing lenght and thickness. They are used to bridge the gap over the door way and are tied into the wall. use when a home is made of block.

The house isn't timber framed - so does that mean that if I went with his advice it would be structurally unsound???

Who do I need to get to install an RSJ?

I don't know as I don't work in that area, But from what I have seen and picked up along the way is that timber of that size would be unacceptable if it were my home. It is a simple enough job and you would need a builder/blocklayer to knit the RSJ in to the fabric of the building and a carpenter to fit door frame and hang door.
Use someone that has done this type of work, it is quite standard so any reputable builder would have done it a lot.