It all started when I discovered that I had high radon levels in my
So I asked someone to install the fan to extract the gas etc. and to
save some money I thought I would caulk the basement cracks myself.
I mean how hard can that be, and so what if it is not the most neat
job, it is in an unfinished concrete basement after all.
Well as with all DIY projects it is not as easy as it looks. The
issue was a crack between the basment concrete wall and the concrete
This crack varies in size between 1/4 inch to almost zero and extends
all the way round my basement. About 200 feet.
I start by using SikaFlex self leveling crack sealant. This stuff
forms a great seal, but dissapears into a bottom less crack. So after
using two tubes of this stuff on like 10 feet of crack and at $US 5
for a 10 oz tube ... time to regroup.
Read somewhere about foam backing rod. OK. go to Home depot and
locate some ... way to thick for the crack. Settle on some self
foam roll sealers for doors and windows. This is thinner and at least
I have a fighting chance in getting it into the cracks. The adhesive
on this stuff is a pain and squeezing it into the crack is slow ...
.... It does work though and I get like 10 feet of crack done in like
There has got to be an easier way. Try some non self leveling crack
Polyeurethane PL Concrete and Masonary. This stuff works, but my hand
is falling off.
I bought one of those cheap caulking guns ... bad bad move. Next trip
Home Depot buy the best one there is at $US 11. Big difference hand
in resonably good shape after 80 feet of caulking.
This Polyurethane stuff is great sticks to the concrete well .... that
it also sticks to hands, face, caulk guns. This stuff gets
Next trip to home depot get some latex gloves. These are well worth
After alot of trial and error, I have finally got the magic formula
So the magical tips for anyone wanting to seal a concrete basement for
1) Get the best Caulk gun there is. Cost $US 11. Your hand will thank
2) Get two sorts of Caulk:
a) Self Leveling Concrete Caulk, Sikaflex, Polyurethane
b) Polyurethane Concrete Caulk. Non self leveling
3) Latex Gloves
4) White Spirits to wash off caulk mess ....
5) Eye-goggles, safety protection.
6) Vaccum cleaner.
I do not have any basdement water issues so all I am trying to do it
caulk a crack.
Step 1: Vaccum out any loose debris from the crack
Step 2: Caulk using the Non-self leveling caulk first.
If required smooth over with your finger to get as much into
crack as you can. This caulk basically stops the self leveling
stuff dissapperaing into the bottom-less void.
Step 3: Go over now with the self leveling sealant. This will close
any small holes for a good gas tight fit.
Step 4: If there are any more holes remaining where the self-leveling
into, due to a void below. Fill with a dab of the non-self
With this technique I found I could make good, if messy progress. Note
both caulks are polyeurethane so that you can apply one on top of the
I hope they are sort of compatible. So far so good, never did
extensive checks on this
Good luck, best, Mike.