De Rat was originally built in the seventeenth century in the
Zaanstreek area of
North Holland. It was known there as
De Walrot () which was generally shortened to
De Rot. Earlier it was thought the mill was in existence in 1683 but archival research,
dendrochronology and an inscription in an old beam show the mill was actually built in 1711. Following the
Napoleonic Wars, the mill fell out of use. At the same time,
agriculture in Friesland was enjoying a boom, with many farms being built or having their old buildings replaced, creating a demand for sawn
timber. In 1828,
De Watterrot was bought at
auction by William Ringnalda and Hessel Aten Vellinga. In 1859, the mill was purchased by Walle Melisz Oppendijk, On 5 December 1955, then-owners NV Houthandel asked for permission to demolish the mill. In April 1956 it was reported that the mill was not in bad condition. It was recommended that permission to demolish it be refused and that the town of IJlst take over the mill. On 17 September 1956,
De Rat was purchased by the town for
ƒ3,000. In 1966, the mill was restored by
millwright J D Medendorp of
Zuidlaren,
Drenthe. The cap and brake wheel came from a
drainage mill at
Scheemderzwaag,
Groningen, which had been demolished in 1959. The windshaft came from the
Monnikenmolen,
Sint Jansklooster,
Overijssel. The mill was used to house a
pottery and afterwards was used by a sailing school. Between 1976 and 1980, the mill was restored to working order. The work was done by millwrights Tacona BV of
Stiens. The fully restored mill was officially reopened on 27 May 1978. Further restoration work was carried out in 1987 and 1996. In 2005, a new cap was made for the mill, replacing the one fitted in 1966 and replicating the original cap in appearance. The new cap was fitted on 19 April 2005. Ownership of the mill now lies with the
Gemeente Wymbritseradiel, while the mill is operated by
Stichting Houtzaagmolen De Rat (). The mill is used as a training mill by the
Gild Fryske Mounders (). ==Description==