Waterproofing concrete basements
Posted by Pick on January 28, 2007
My city will not allow me to put a perforated drainage pipe around the basement I am planing. Instead I must find some way to make my concrete basement floor and walls waterproof (much like the hull of a ship!) so that they can withstand any hydrostatic pressure from seasonal ground water. I’m wondering if there is any way to make concrete absolutly waterproof and if so, would this solution last over 10 or even 50 years?
Based on the way you have asked the question, I am assuming that it’s not an existing basement and you are planning to build it new.
There are several systems of basement waterproofing available in the market, internet is a good tool to find them. A general guideline for basement waterproofing would as described below.
For the base concrete slab:
Before casting the base slab, below the base slab on the gravel base, place a 4” thick lean to normal concrete mix. Coat this concrete with a bituminous coating. Lay a sheet of waterproofing membrane and place the base concrete on this sheet.
The base concrete should be of low water to cementitious ratio, if possible use either fly ash or slag in appropriate amounts to reduce the porosity of the concrete. Use a water reducing admixture (mid or high range) to achieve a manageable workability with the low w/c ratio concrete. Addition of latex polymer to the concrete will help the concrete to be more impervious.
For side walls:
If the side walls will be of concrete, use similar concrete which was used for the base concrete. If the side walls are made of blocks, use solid blocks made using a water repelling admixture in it. Use either a water repelling or a integral water proofing admixture in the mortar used for filling the joints. If possible plaster the wall from outside with a cement-sand mortar. Coat the outside of the wall (or plaster) with a bituminous waterproof coating and cover the wall from outside will the waterproofing sheet membrane, if the basement wall is exposed to soil. If you want additional protection you can fill the gap between the outside wall and the solid with a bentonite slurry.
I think this will give you a pretty strong and durable basement structure.
garden ornaments
Posted by david on January 28, 2007
What is the best cement to use,as i see other m.f,g ornaments and they seem to be far more solid than mine
The main parameter which influences the strength of any concrete product is the water to cement ratio of the concrete. If you want to make strong and dense concrete, you have to use a low water to cement ratio.
To achieve a manageable or workable concrete with the reduced water to cement ratio, you can use a water reducing admixture (low, mid or high range) in the concrete. The water reducing admixture will compensate for the lack of fluidity in the mix caused due to the lower water to cement ratio.
