Error In sql Server " Conversion failed when converting the varchar value '%' to data type int."

ALTER PROCEDURE [dbo].[csp_Objekt_GetAllObjekts]      
(                                            
		@StreetNo int,                -- Search option 		
		@FirstRow Int,						      -- Starting Row Number
		@LastRow Int,							  -- Ending Row Number
		@SortColumn varchar(30),				  -- Sort Column Name
		@SortOrder varchar(4)					  -- Sort Direction (ASC/DESC)
)

AS
SET NOCOUNT ON
DECLARE @OrderBy varchar(40)

-- Setting Sort Column and Sort Order null for empty value
IF @SortColumn IS NULL
SET @SortColumn=ISNULL(@SortColumn,'')
IF @SortOrder IS NULL
SET @SortOrder=ISNULL(@SortOrder,'')

-- Combining Sort Column and Sort order
SET @OrderBy=@SortColumn+@SortOrder

SELECT * FROM
(
SELECT ROW_NUMBER() OVER(ORDER BY

-- Sorting StreetNo as Ascending order
CASE
WHEN @OrderBy = 'StreetNoASC' THEN StreetNo
END ASC,
-- Sorting StreetNo as Descending order
CASE
WHEN @OrderBy = 'StreetNoDESC' THEN StreetNo
END DESC,

-- Default Sorting by ObjektName
CASE
WHEN @OrderBy = '' THEN ObjektName
END ASC
) AS RowNum,

COUNT (*) OVER () AS TotalObjekts,

ObjektId,
ObjektName,
Street,
StreetNo,
Land,
PLZ,
Ort,
CreatedDate,
IsContactPerson,
IsDocument,
IsPhoto,
Notice
FROM
Objekt WITH(NOLOCK)
WHERE
-- Filtering StreetNo      
(@StreetNo IS NULL OR @StreetNo = 0 OR StreetNo LIKE @StreetNo + '%')

)AS ObjektsData
WHERE RowNum >=@FirstRow AND RowNum<=@LastRow -- Taking only the given range records
SET NOCOUNT OFF