# Pre-Drill holes in timber landscape for Galvanized Spike?



## svaic00 (Jul 2, 2012)

Hello,

I am leveling out the ground for an area for my kids playset. In order to do that with the yard slope that I have, I am using 4x4 ground contact PT timbers to make a small retaining wall/boxing out the area for the playset and mulch. 

I am using #5 rebar to attach the bottom two layers to the ground (pre-drill hole and hammer through into the ground 3 to 4' deep), and using 3/8" x 8" long galvanized spikes to attach the 4x4 layers to each other. My question is, what size hole should I pre-drill for the 3/8" spikes so as not to split the wood?

I have found one blog that mentioned the pre-drilled hole should be about 2/3rd the size of the spike. So 2/3rd of 3/8" = 0.25". Should that work? I was assuming that bumping that up to 5/16 pre-drilled would be too large of a hole, and the spike may lose its gripping power and not hold as tight since that hole size is too close to the actual dimension of the spike.

Thanks in advance,
Steve


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## jlhaslip (Dec 31, 2009)

Should be fine with the 1/4 inch size.
Can you locate any large spiral nails? They hold better.


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## de-nagorg (Feb 23, 2014)

1/4 inch should work great.

A lag bolt, countersunk into the top 4X4, would be better, never loosen, and sunk deep enough to prevent any skin tears if a child happens to trip and fall on it.

Drill a 1/4 bore hole, Countersink a 1.25 recessed hole, use a large flat washer on a lag bolt, then cap the hole with a wood plug glued in.


ED


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## joecaption (Nov 30, 2011)

This is what I use.
https://www.lowes.com/pd/FastenMaster-50-Count-6-in-Structural-Wood-Screws/3295080


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## Bondo (Dec 8, 2007)

joecaption said:


> This is what I use.
> https://www.lowes.com/pd/FastenMaster-50-Count-6-in-Structural-Wood-Screws/3295080



Ayuh,.... I dug a 10 lb pail of them, in 8" outa a dumpster a few years ago,...

Extremely robust screws, for Sure,....
Used 'em to tie back a fake roof overhand on the river house, that the nails were slidin' out on,...
Deb can now hang plants off it,....


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