I'm building a wooden porch on the front of my house. I have six 4" wooden pillars supporting the structure. It's light, doesn't contain concrete, roof tiles, etc, and is made entirely of wood. I'm digging footings and am about to install the pillars. I'm wondering whether to set the wooden pillars into the concrete or simply sit them on top.
I realise setting them into the concrete will mean they might move less laterally but I'm concerned that with the wood in the concrete there is more chance that moisture will slowly get in between the concrete and timber and rot the wood. It is not hardwood by the way. So should rotting occur in future, it will be easier to replace a pillar if they are not set in concrete - and I figure they are less likely to rot anyway if they are not set in the concrete in the first place.
So what's best - to set the pillars into concrete, or to just sit them on top?
My concrete footings are about 2.5 ft deep, 12 inches round for each pillar. I'm putting a metal mesh into each one to assist in concrete strength.