Fencing posts - 3x3 / 4x4

[mrcw]

What is the advantages of using 4x4 timber softwood posts for fixing lap panels to, rarther then 3x3, do they last longer, and are they better for panels of a certain height Ie 5ft / 6ft

Regards

[dig dug dan]

4x4 posts do not twist and bend like 3x3. They last 4 times as long, and will make the whole fence stronger.
I only use 3 x 3 for 3-4' Max height , and I always use a gravel board under each panel.
Also, dont forget post caps. Stops the to of the post from rotting!!

a fence I put up 12 years ago for a customer is still going strong. But a fence I put up about 4 years ago for a relative (they insisted on 3x3 to save money), is always having posts snap off in the winds! quality speaks for itself!

:;):

[mrcw]

Cheers

[Tony McC]

The strength of a post is proportional to the square of its size. To keep it simple, consider it this way: a 3x3" post has a cross-sectional area of 9 square inches, while a 4x4 has an area of 16 square inches, so although the dimensions have only been increased by 33%, the strength is increased by over 75%

[mattrgee]

I used 3x3 posts for a project a couple of years ago, the posts are still looking good, but in heinsite, I would use 4x4 or even 5x5's. I've heard of some people using a mixture of 4x4's and 5x5's, with 5x5's for the corner posts and 4x4 else where.

[mrcw]

Just seen some in a bourchre 75 x 100

Which way would you have them facing the front the 75 or the 100

Never seen that size before, or are they for a special type of fence

[steve r]

75 x 100 or more commonly 75 x 125mm are normally used for post and rail fencing, with the longest side in line with the rails.