Answers to frequently asked questions.

What precautions should be taken when working with JAHN mortars in extreme weather conditions?
The application instructions give a working range of 40° to 90°, and state that repairs must be protected from extreme heat, freezing, excessive wind, direct sunlight and rain. It is possible to work above and below that range, as well as during the other conditions, but precautions must be taken. Contractors that are working in hot and cold weather should always follow the local building codes regarding material protection, heating of materials, use of frozen materials and protection of completed work. Click here for detailed instructions.

How can I get the best mortar color match?
Select an area you will be patching that shows the color you want. Chip a piece of the substrate off (2" x 2" minimum). Hold the sample you have removed up to other places you intend to repair and verify it matches. If it doesn't match you may need more than one color match. Once you have collected your samples place a mark on the side that matches the color you want and place each sample in a sandwich bag. Fill out the color sample information sheet and ship samples to Cathedral Stone Lab.

When you get your mortar samples install them in the same area you removed the stone chip. Install mortar according to application instructions and finish to match surrounding substrate. Wait a minimum of 3 days after installing mortar to evaluate colors. This will ensure you get the most accurate color match.

Why do some patches get a white haze?
This haze is most commonly seen in dark colors and is a result of moisture. The source of the moisture can be in the substrate or humidity in the air. If you can, cover the work area to prevent additional moisture from getting to the substrate. If that's not possible you may need to wait until weather conditions improve.

Why do some patches get lighter than others?
Water will lighten the color of your mortar. Careful measuring and mixing will help eliminate this. If your repair is fresh and it begins to rain or heavy dew sets in, the pigment on the surface is diluted and the patch will lighten. Keep an eye on the weather and keep plastic handy. Cover patches loosely so the plastic doesn't touch the patch.

Can I change the color of a repair that's cured?
Patches can be stained using the Cathedral Stone Masonry Mineral Stain System. This is also an easy way to enhance or add multiple colors to repairs.

How deep can I install the mortar?
With the exception of a few mixes (M100, M110-JB and M120 which need to be installed in 1" lifts) the mortar has no depth limitations.

Can I work in lifts/layers?
Lifts are not a problem. Just make sure the surface of your first lift is rough. The second lift will use the same application procedures as the first.

When should I use pins/anchors?
It varies. Any repair area that could potentially fail and cause damage or injury should be pinned. The pins should be threaded stainless steel. Use common sense to determine spacing or consult with the project architect or engineer.

Which Cathedral Stone Paint Stripping System should I use?
The best way to determine which paint stripper is best suited for your project is to request samples of our paint strippers and test the area to see which product works best.

What is the best way to apply the paint stripper?
Use an airless sprayer for large areas and trowel on smaller jobs. This material only works while it is wet, so the thicker the layer you apply the better. Once the stripper dries, it stops working.

How long will the stripper take to remove the paint?
Dwell time depends on many factors. The lower the temperature the longer it will take to work. You should be able to see the paint lift when it takes effect. Again, apply a thick coat so the stripper doesn't dry out before the paint is stripped. If it dries out, you will need to reapply but after about 4 hours you can test your results. Some coatings require 24+ hours to release. Do not allow the paint stripper to dry out or you will need to reapply.

Will the Cathedral Stone R-97 Water Repellent System change the color of the substrate?
No. When dry, the coating is invisible.

Will the Cathedral Stone R-97 Water Repellent System harm glass?
No. However, be sure the glass is clean. Dirt on the glass will react with the R-97 and be much harder to clean off after.

What is the coverage rate for Cathedral Stone R-97 Water Repellent System?
The coverage rate will vary depending on the porosity of the substrate. However, 100 to 200 square feet per gallon can be expected.