Porth Mawr, Mostyn Hall

Central gabled range contains a gate-passage to courtyard; the ceiling has 3 stop chamfered beams, and a cross-beam at right angles (along R side of the passage) with an original inscription 'WM 1570' and 'Anno Mundi 1552'. The passage has a flagstone floor and doors to L and R. From the exterior, the doorway in the R return of the central gabled range leads to a staircase; to R, the 1st floor is open to the roof with Queen-post trusses and 2 rows of trenched purlins to each pitch. Inserted partitions and boarded doors leading off corridor, with office at E end. Leading L from the staircase, the 1st floor of the gabled range has fine moulded plaster ceilings, decorated with curved ribs and foliate bosses. Parts of the walls are similarly plastered. This area was unused at the time of inspection but was previously grooms' accommodation. To the L of the central gabled range, the ground floor was formerly stables, with 4 loose boxes divided by planked partitions and railings; tack room to R.

Long 2-storey range with a 3-storey cross-gabled block to centre, advanced to S (entrance) side. To courtyard (N) side is a large cross-wing to L and a smaller cross-wing to R. Constructed of partly coursed rubble with freestone dressings (with various masonry breaks), under slate roofs. Stone stacks with brick shafts, raised copings to gables with finials, toothed quoins to L wing. The range to L of central gabled block has a tall weather vane to far L. Mainly stone mullioned windows, of 2-, 3- or 4-lights, some with transoms; planked doors with stone voussoired heads. The S side has a narrow round-arched entrance with studded door to central gabled block leading to a through-passage. Two 2-light windows to 1st floor with cambered stone relieving arches; central transomed 3-light window in stone surround to 2nd floor. Doorway with segmental head to R return leading to staircase; lateral stack with diagonally-set brick shaft to L return. Planked door with segmental head R of centre leading to loose boxes, flanked by 2-light mullioned windows. Three windows with diamond quarry glazing to upper storey; a pair of small 2-light mullioned windows to L, probably original, with similar blocked window R of centre. Larger 3-light window to R with blocking beyond. To R range, large lateral stack with 2 diagonally-set brick shafts to far R. Three segmental-arched doorways, with overlights to L and centre, and containing a studded door to R. Single 2-light window to upper storey. The gable end of the cross-wing has a large stack to apex with grouped diagonally-set brick shafts and a 2-light stone mullioned window to 1st floor.

The W side of the cross wing has a narrow full-height gabled projection to the R, possibly to house a staircase or garderobe. Single light to ground floor, and 2-light stone window to attic; further single light at mid-level to R return. In the R angle of the wing and outshut is a massive stone lateral stack, with stepped brick shaft. To L of outshut is a 3-light mullioned window with hoodmould to each storey, probably C19, and tiny light to far R.

To courtyard (N) side: wide segmental-headed doorway to gate-passage, offset to R of central gabled range; 3-light mullioned and transomed window with hoodmould aligned above to 1st floor, with an inscription '1570 WM'. Small round-headed stairlight to its L, and small blocked light below. Similar window to centre of 2nd storey with moulded sill. Range to L has 4 tall round-headed lights to upper storey with keystones and imposts. To lower storey are 2 blocked round-headed doorways (shown by Pennant in 1796), each with a blocked 2-light mullioned window to their L. To far L, 2-light mullioned window and blocked segmental-headed doorway. The gable end of the E cross-wing has a studded door in renewed square-headed surround, offset to the R. Two-light mullioned windows to centre of ground, 1st and attic storeys, of different sizes. Two-window R return has round-headed doorway and similar light above, and 2-light windows to their L; attic dormer with similar window. To R of central gatehouse, blocked round-headed doorway, flanked by large 3-light mullioned window to L, and 4-light window to R. Upper storey has from L, blocked opening, 3-light mullioned window with small infilled opening below, and a pair of 2-light windows to R. The R wing has a large domed bell cupola to ridge, with diamond clock attached to gable. Three-light mullioned window with hoodmould to 1st floor, and similar blocked window below; boarded door with segmental head to L return. West gable end of main range has blocked Tudor-arched doorway offset to L. Small lean-to in angle of W end and R wing.