Hi
I have a fence post that will go up against my house

The old post was not concreted into the house but just screwed in.

The new fence is quite a big bigger.

It is 2.4m and 10cm b 10cm. It will be 1.8m above ground and 60cm below
ground.

It seems silly not to screw this one against the wall as well

Question is how?

Will I need a screw that will go all the way through the post and into the
house? so it will have to be maybe 15cm long, with a wall plug that is 5cm
long

I have heard of hammer in fixings, but can i get one this big and are they
as strong as traditional wall plug method?

I plan of putting in 3 screws, top, middle and bottom.