Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Hi my question has 2 parts about piles and creating a subfloor.

I want to install a 4.8x4.8m (~16'x16') summerhouse; its existing floor is 24mm (~1") floor boards on 75x50mm (~"2x3") floor posts.

I don’t want a concrete base so I thought I could create my own piles using 110mm (~4.5") pipe (filled with postcrete and topped with damp-proof membrane) for the sub floor to rest on.

Is 110mm (~4.5") good enough or should I get 150mm (~6")? How deep should I go with the piles and at what spacing.

I then want to create a base frame for the summerhouse to go on and was thinking that as it already comes with a 75x50mm (~"2x3") floor I could create another one (joist running the opposite way) with 75x50mm (~"2x3") timbers.

Are these good enough timbers for the sub floor as I don’t want to go too high either? what spacing should I have between them?

share|improve this question
Can you define 'pile'? I think that term might mean something slightly different from region to region. –  DA01 Sep 25 '13 at 15:16
It really depends what kind of soil this is going in. Where are you at and has the soil been undisturbed? –  DMoore Sep 25 '13 at 17:04
@DA01 "Pile" is an accurate term, but you might think of it as a foundation "pier". In essence, columns that extend underground to create foundation points. Most often used for underpinning/foundations of decks and sheds, or in addition to standard foundations either where support columns will be located above or where unstable grade would pose a problem, in residential construction. –  Jacob S Sep 25 '13 at 17:09
I'm not sure I get what you're asking. Do you have an already constructed house that you want to move to a new location? –  Chris Cudmore Sep 25 '13 at 17:21
@JacobS that makes sense. I've always heard the term "piling" but now that I think about that, that's just the plural of pile. ;) –  DA01 Sep 25 '13 at 17:35

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.