Wood Flooring International Moisture Meter Settings Chart

Note: as WFI completes the tests on each species we add the results to the chart below.

Below we review how you should use the linked Shrinkage and Moisture Meter Settings Chart.

Measuring Moisture Content - Each wood species has different electrical properties which distort the readings taken by a moisture meter, which measures the electrical resistance between the inserted probes to determine how wet the wood is. Most meters use Douglas fir as the standard to which they set the meter to. As result, you need to correct the readings taken by your moisture meter for the specific electrical properties of the species being tested.

We use a Gann Hydromette HT 85 moisture meter which allows us to temperature correct the meter to the temperature of the wood being tested and then to choose one of four specie correcting settings, which vary ~1.7% points between each. We then advise which Gann specie setting to use and when set on that setting, what variance you need to add/subtract for that species. You can visit Gann's web site here http://www.gann.de/ for more information on their meters.

For those of you who have different meters then a Gann moisture meter, we have included a chart which advises what % to add/subtract from a red oak setting. In this case, you simply set your meter to the red oak setting, take the readings, and then add/subtract by correcting factor listed in the linked chart in the correction to Red Oak column. Warning Note: As each type of meter is different, we cannot assure you that this table will be correct when used with your meter !

Shrinkage Coefficient ‑ Each wood species' dimensions will change slightly as it deviates from a normal moisture content of between 6‑8%. The degree to which they change can be estimated using the species' shrinkage coefficient, a number that reflects a species' relative stability and developed by measuring the changes to a wood flooring's face width and moisture content as it dries from the normal 6‑8% MC down to 0% during oven testing. We run these tests on both straight grain pieces (always more stable) and flat sawn pieces. The lower the shrinkage coefficient, the more stable the species.

The expected amount of shrinkage or swelling can be calculated by multiplying the change in moisture content by the shrinkage coefficient, then multiplying by the board's width.

Example

        3" Brazilian Cherry (straight grain shrinkage coefficient = .00218) dried from 8% moisture content down to 6%.
                                  Expected change in face width = % change in MC x shrinkage coefficient x face width
                                                                                   = 2% change x .00218 x 3 in. wide
                                                       Expected change = .013 in. or.33mm*

*Conversion factor: 1 in. = 25.4 mm

A completely installed floor would however force boards together in a way that tends to restrain such movement.

Note: We do not recommend the use of non-pin type moisture meters.
See bottom of chart for more details about sets of data:

Domestic Species - to North America by Flooring Trade Name
Species	Moisture Meter Correction			Shrinkage Coefficient
Species	Gann HT85 Setting	Gann Correction	Correction to Red Oak	Flat Sawn	Straight Grain
Ash, White	#2	-0.1%	-1.8%	0.00277	0.00202
Cherry, N. American	#3	-0.3%	-0.3%	0.00303	0.00206
Maple, N. American	#3	+1.6%	+1.6%	0.00298	0.00192
Oak, Red	#3	+0.0%	+0.0%	0.00198	0.00161
Oak, White	#2	+1.0%	- 0.7%	0.00199	0.00154
Walnut, N. American	#3	+1.2%	+1.2%	0.00219	0.00182
Imported Species - to North America by Flooring Trade Name
Species	Moisture Meter Correction			Shrinkage Coefficient
Species	Gann HT85 Setting	Gann Correction	Correction to Red Oak	Flat Sawn	Straight Grain
Afrormosia	#2	-0.7%	- 2.4%	0.00329	0.00190
Amendoim	#4	+0.7%	+ 2.4%	0.00251	0.00213
Ash, Silky	#1	+1.3%	- 2.1%	0.00311	0.00270
Ash, Victorian (Oak, Tasmanian)	#3	-0.2%	-0.2%	0.00318	0.00227
Bamboo	#2	+1.0%	-0.7%	(H) 0.00211	(V) 0.00168
Beech, European	#3	+0.2%	+0.2%	0.00346	0.00199
Bloodwood	#3	+2.0%	+2.0%	0.00253	0.00213
Brushbox, Northern	#2	0.0%	-1.7%	0.00394	0.00362
Cherry, Bolivian (Massaranduba)	#2	0.0%	-1.7%	0.00234	0.00197
Cherry, Brazilian	#3	-0.2%	- 0.2%	0.00289	0.00218
Cherry, Caribbean (Mayan/Aztec)	#2	+3.3%	+1.6%	0.00413	0.00243
Cherry, Chilean	#2	+3.3%	+1.6%	0.00413	0.00243
Cherry, Patagonian	#3	+1.5%	+1.5%	0.00302	N/A
Chestnut	#2	+2.4%	+1.7%	0.00184	0.00328
Chestnut, Southern	#3	+0.2%	+0.2%	0.00367	0.00302
Cypress, Australian	#3	+0.3%	+0.3%	0.00374	N/A
Doussie	#2	+1.0%	- 0.7%	0.00244	0.00138
Species	Moisture Meter Correction			Shrinkage Coefficient
Species	Gann HT85 Setting	Gann Correction	Correction to Red Oak	Flat Sawn	Straight Grain
Gum, Sydney Blue	#3	+0.3%	+0.3%	0.00314	0.00190
Iroko/Kambala	#2	- 0.5%	-2.2%	0.00192	0.00125
Jarrah	#3	+1.1%	+1.1%	0.00236	0.00274
Kempas	#3	+0.9%	+0.9%	0.00357	0.00308
Lacewood	#3	-1.3%	-1.3%	0.00173	0.00262
Mahogany, Honduran	#3	+2.3%	+2.3%	0.00241	0.00184
Mahogany, Royal	#1	0.0%	- 3.4%	0.00261	0.00202
Mahogany, Santos	#3	+0.8%	+0.8%	0.0234	0.00163
Maple, Patagonian (Brazilian)	#3	0.0%	0.0%	0.00231	0.00207
Merbau	#3	+0.3%	+0.3%	0.00289	0.00223
Pine, Heart	#3	+1.7%	+1.7%	0.00268	0.00240
Purpleheart	#3	+4.0%	+4.0%	0.00289	0.00262
Rosewood, Bolivian	#2	+3.2%	+1.5%	0.00205	0.00146
Species	Moisture Meter Correction			Shrinkage Coefficient
Species	Gann HT85 Setting	Gann Correction	Correction to Red Oak	Flat Sawn	Straight Grain
Rosewood, Caribbean	#2	+0.8%	- 0.9%	0.00211	N/A
Rosewood, Patagonian	#3	+1.3%	+1.3%	0.00324	N/A
Rubberwood	#2	+0.5%	-1.2%	0.00017	0.00017
Shedua/Mutenye	#2	+4.3%	+2.6%	0.00323	0.00188
Teak, Brazilian	#3	+0.7%	+0.7%	0.00364	0.00312
Teak, True	#3	+0.6%	+0.6%	0.00176	0.00138
Tigerwood	#3	+3.2%	+3.2%	0.00228	0.00147
Timborana
Walnut, Brazilian	#2	+2.5%	+0.8%	0.00307	0.00266
Walnut, Caribbean (Mayan/Aztec)	#3	-3.5%	-3.5%	0.00349	0.00291
Walnut, Patagonian	#2	+3.3%	+1.6%	0.00319	0.00197
Walnut, Peruvian	#2	+2.2%	+0.5%	0.00328	0.00188
Wenge	#2	+2.1%	+0.4%	0.00302	0.00235
Zebrawood	#3	- 2.4%	- 2.4%	0.00276	0.00220

All of the published results above are from oven tests made in WFI's lab as follows:

For moisture meter correction, we compare the Gann moisture meter readings to actual oven tests, whereby we test at least six different samples of floors typically reading 6-8% on the meter and then oven dry them to 0% and use the data to develop the Gann adjustment factor.
For shrinkage, we first measured the face width and moisture content and then dry them to 0% on wood 3" flat sawn and straight grain flooring samples to develop the shrinkage coefficient in both straight grain and flat sawn flooring.
Call or e-mail andrew@wflooring.com for individual test results.
Disclaimer: These results were found in our lab based on the samples of wood tested. They may vary from other samples and from the same species growing elsewhere. Therefore, WFI cannot assume any liability for your use of this data.

*Note: Rubberwood shrinkage taken from end to end, not across the face.